Question about 1991 Chevrolet Lumina

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91 z34 idlestoo fast. replaced tps,iav, and map sensors. no change. obd wont read a signal.

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If car has a carburetor instead of fuel injection, lokk down into the throat of the carburetor and see if you can see small amount of fuel dripping, if so the needle and seat inside the caruretor are probably dirty and stuck, causing you the problem. Could also have a vacuum hose off or cracked/broken.

Posted on Apr 30, 2010

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1 Answer

Smog code p0108


this is for the MAP sensor , it can also be a wiring fault and not the actual sensor so i've copied and pasted to save time a guide
Symptoms Possible sumptoms of OBD code P0108
MIL (Malfunction Indicator Lamp) will likely be on Engine may run poorly Engine may not run at all Fuel mileage may decrease Presence of black smoke at exhaust
Causes Possible causes of OBD code P0108
Bad MAP sensor Leak in vacuum supply line to MAP sensor Engine vacuum leak Short on signal wire to PCM Short on reference voltage wire from PCM Open in ground circuit to MAP Worn engine causing low vacuum
Possible Solutions A good way to diagnose if the MAP sensor is to blame would be to compare the KOEO (key on engine off) MAP sensor reading on a scan tool with the Barometric pressure reading. They should be the same because they both measure atmospheric pressure. If the MAP reading is greater than 0.5 volt off of the BARO reading, then replacing the MAP sensor would likely fix the problem. Otherwise, start the engine and observe the MAP reading at idle. It should normally be about 1.5 volts (varies according to altitude). a. If it is, the problem is likely intermittent. Check all the vacuum hoses for damage and replace as necessary. You can also try wiggle testing the harness and connector to reproduce the problem. b. If the scan tool MAP reading is more than 4.5 volts, check the actual engine vacuum reading with the engine running. If it is less than 15 or 16 in. Hg, then the PCM is probably not seeing enough vacuum (due to a worn engine, perhaps) for a given operating condition (which causes a higher than normal voltage signal to the PCM) and setting the code. Repair the engine vacuum problem and retest. c. But, if the actual engine vacuum reading is 16 in. Hg or more, then unplug the MAP sensor. The scan tool MAP reading should indicate that there is no voltage present. Check that the ground from the PCM is intact and also that the MAP sensor connector and terminals are tight. If the connection is good, then replace the map sensor. d. However if, with KOEO, & the MAP sensor unplugged, the scan tool shows a voltage reading, then there may be a short in the harness to the MAP sensor. Turn the ignition off. At the PCM unplug connector and remove the MAP signal wire from the connector. Re-attach the PCM connector and see if with KOEO, the scan tool MAP reading shows voltage. If it still does, replace the PCM. If not, check for voltage on the signal wire you just removed from the PCM. If there is voltage on the signal wire, find the short in the harness and repair.

hope this helps

Jul 08, 2014 | 2001 Pontiac Sunfire

2 Answers

DTC code P109


It states 94 cadi and it is not OBD2 so the code is P109 and not P0109.
your information is incorrect.
P109 and p052 is internal to PCM ck sum issues, Possible due to battery connections loss of voltage.

Jun 22, 2012 | 1994 Cadillac Seville

1 Answer

I have a 94 blazer and the check engine soon light came on and shortly after it started hesitating when i would hit the gas


Hi, the problem may be at the TPS or the MAP sensor. First extract the trouble code following instructions below. Then troubleshoot the indicated signals/sensors.


jturcotte_2348.gif



Fig. Fig. 1: ALDL connector-1994 models

Listings of the trouble for the various engine control system covered in this guide are located in this section. Remember that a code only points to the faulty circuit NOT necessarily to a faulty component. Loose, damaged or corroded connections may contribute to a fault code on a circuit when the sensor or component is operating properly. Be sure that the components are faulty before replacing them, especially the expensive ones. The Assembly Line Diagnostic Link (ALDL) connector or Data Link Connector (DLC) may be located under the dash and sometimes covered with a plastic cover labeled DIAGNOSTIC CONNECTOR.

  1. On all 1994 models the diagnostic trouble codes can be read by grounding test terminal B . The terminal is most easily grounded by connecting it to terminal A (internal ECM ground). This is the terminal to the right of terminal B on the top row of the ALDL connector.
  2. Only 1995 models equipped with a PCM use the OBD I system. All other 1995 and later models use the OBD II system. The diagnostic trouble codes on 1995 OBD I systems can be read by grounding test terminal 6 . The terminal is most easily grounded by connecting it to terminal 5 (internal ECM ground).
  3. Once the terminals have been connected, the ignition switch must be moved to the ON position with the engine not running.
  4. The Service Engine Soon or Check Engine light should be flashing. If it isn't, turn the ignition OFF and remove the jumper wire. Turn the ignition ON and confirm that light is now on. If it is not, replace the bulb and try again. If the bulb still will not light, or if it does not flash with the test terminal grounded, the system should be diagnosed by an experienced driveability technician. If the light is OK, proceed as follows.
  5. The code(s) stored in memory may be read through counting the flashes of the dashboard warning lamp. The dash warning lamp should begin to flash Code 12. The code will display as one flash, a pause and two flashes. Code 12 is not a fault code. It is used as a system acknowledgment or handshake code; its presence indicates that the VCM can communicate as requested. Code 12 is used to begin every diagnostic sequence. Some vehicles also use Code 12 after all diagnostic codes have been sent.
  6. After Code 12 has been transmitted 3 times, the fault codes, if any, will each be transmitted 3 times. The codes are stored and transmitted in numeric order from lowest to highest.
The order of codes in the memory does not indicate the order of occurrence.
  1. If there are no codes stored, but a driveability or emissions problem is evident, the system should be diagnosed by an experienced driveability technician.
  2. If one or more codes are stored, record them. Refer to the applicable Diagnostic Code chart in this section.
  3. Switch the ignition OFF when finished with code retrieval or scan tool readings.
jturcotte_2355.gif

MAP sensor tests:
TESTINGSee Figures 1, 2 and 3

jturcotte_2349.gif

Fig. Fig. 1: Typical Manifold Absolute Pressure (MAP) sensor wiring diagram (wire color, terminal identification/location may vary on certain models)

  1. Backprobe with a high impedance voltmeter at MAP sensor terminals A and C .
  2. With the key ON and engine off, the voltmeter reading should be approximately 5.0 volts.
  3. If the voltage is not as specified, either the wiring to the MAP sensor or the VCM may be faulty. Correct any wiring or VCM faults before continuing test.
  4. Backprobe with the high impedance voltmeter at MAP sensor terminals B and A .
  5. Verify that the sensor voltage is approximately 0.5 volts with the engine not running (at sea level).
  6. Record MAP sensor voltage with the key ON and engine off.
  7. Start the vehicle.
  8. Verify that the sensor voltage is greater than 1.5 volts (above the recorded reading) at idle.
  9. Verify that the sensor voltage increases to approximately 4.5. volts (above the recorded reading) at Wide Open Throttle (WOT).
  10. If the sensor voltage is as specified, the sensor is functioning properly.
  11. If the sensor voltage is not as specified, check the sensor and the sensor vacuum source for a leak or a restriction. If no leaks or restrictions are found, the sensor may be defective and should be replaced.
jturcotte_2350.gif

Fig. Fig. 2: Using jumper wires and a high impedance voltmeter test between MAP sensor terminals A and C with the key ON and engine off. The voltage should be approximately 5 volts


jturcotte_631.jpg

Fig. Fig. 3: Next test between MAP sensor terminals A and B with the key ON and engine off. The voltage should be approximately 0.5 volts

MAP sensor
jturcotte_632.jpg

Throttle position sensor test
TESTINGSee Figures 1, 2 and 3

  1. Backprobe with a high impedance voltmeter at TPS ground terminal and 5 volt reference signal terminal.
  2. With the key ON and engine off, the voltmeter reading should be approximately 5.0 volts.
  3. If the voltage is not as specified, either the wiring to the TPS or the VCM may be faulty. Correct any wiring or VCM faults before continuing test.
  4. Backprobe with a high impedance voltmeter at the TP signal terminal and the sensor ground terminal.
  5. With the key ON and engine off and the throttle closed, the TPS voltage should be approximately 0.5-1.2 volts.
  6. Verify that the TPS voltage increases or decreases smoothly as the throttle is opened or closed. Make sure to open and close the throttle very slowly in order to detect any abnormalities in the TPS voltage reading.
  7. If the sensor voltage is not as specified, replace the sensor.
jturcotte_2352.gif

Fig. Fig. 1: Common Throttle Position Sensor (TPS) wiring diagram (wire color, terminal identification/location may vary on certain models)





jturcotte_2353.gif

Fig. Fig. 2: Using jumper wires and high impedance voltmeter, test between the sensor ground and reference terminals, the voltage should be approximately 5 volts


jturcotte_2354.gif

Fig. Fig. 3: Next test between the sensor signal and ground terminals, verify that the TPS voltage increases or decreases smoothly as the throttle is opened or closed

Oct 01, 2011 | 1994 Chevrolet S-10 Blazer

1 Answer

95 cadillac reading code current p105 sometimes engine light comes on sometimes harder to start than normal, idles up and down up on stopping


Symptoms Symptoms of a P0105 check engine light code may include:
  • Poor running engine
  • Engine runs rich
  • Engine won't idle
  • Engine backfires through tailpipe
  • Engine misfire under load or at idle
  • MIL (Malfunction Indicator Lamp) illumination
  • In some extreme cases there may be no symptoms other than MIL illumination
Causes A P0105 DTC could be caused by:
  • MAP sensor vacuum hose disconnected or plugged
  • Bad MAP Sensor
  • Bad TPS
  • Damaged or problematic MAP sensor connector
  • Damaged or problematic TPS connector
  • Damaged wiring
  • Short to reference voltage on signal circuit of MAP Sensor
  • Loss of ground to MAP sensor or TPS
  • Open on signal circuit of MAP sensor
  • Bad PCM
Possible Solutions Using a scanner or code reader, turn the ignition on and engine OFF; what does the MAP sensor voltage read? It should be about 4 Volts for sea level. If you are at a higher altitude, it should decrease about half a volt or so for each 1,000 ft. of altitude (this will vary from model to model) Or if you have a separate MAF (Mass air flow) sensor on your vehicle, they are usually equipped with a Barometric pressure reading. If so, the Baro reading should match the MAP reading (they both measure ambient air pressure). If they're roughly equal, then, check for Freeze Frame data of the MAP sensor (if available).
NOTE: Freeze Frame data is the PCM recording a fault when it happens. It captures the readings of the various PIDS (parameter identifiers)available to troubleshoot what happened. It's like a recording of the problem as it happened. At idle a typical MAP sensor Voltage reading should be about a volt, and at WOT (wide open throttle) it should approach 4.5 to 5 Volts. As for the TPS, at idle, the voltage reading is about 1 Volt or less. As the throttle is opened the reading will increase to 4.5 Volts at WOT. Do the two readings make sense? For example, if the TPS reading on Freeze Frame data shows 2.5 Volts (indicating partial throttle) does the MAP sensor indicate a reading that isn't at either extreme? Using the Freeze Frame data (if available) compare the MAP reading to the TPS when the problem occurred. This can help you identify what happened
If you have no access to Freeze Frame data then check if the MAP sensor voltage changes when you apply vacuum to it. You can do this by mouth or a vacuum pump. The voltage should increase as you apply vacuum. If the reading doesn't change as you apply vacuum, make sure there are no obstructions in the hose to the sensor. If the hose is clear, the MAP sensor is usually bad, but it doesn't rule out the following from causing the problem: Does the MAP sensor appear to be stuck at less than .5 Volts? Then:
NOTE: This code shouldn't set if the MAP is stuck at extremely low voltage, however, I'm adding it in because there's no way to know for certain for which vehicles a low voltage condition may set a P0105
  1. Inspect the wiring harness and MAP sensor connector. Repair any damage
  2. Unplug the MAP sensor connector. Also, at the PCM connector, remove the MAP sensor signal wire and check for continuity to the MAP sensor connector. If there is infinite resistance, then repair open in MAP signal circuit. If the signal wire has continuity to the MAP sensor connector, then check for 5 volt reference voltage to the connector and a good ground. If both are present, then re-install all removed wiring and replace the MAP sensor.
Does the MAP sensor appear to be stuck at full 4.5 voltage? Then:
  1. Inspect the wiring harness for damage. Repair as needed
  2. Remove the MAP sensor signal wire from the PCM connector. With a voltmeter measure the voltage with KEY ON ENGINE OFF. Is there 4.5 Volts? If so, unplug the MAP sensor and recheck. If it is still present, then repair short between the signal wire and 5 volt reference wire.
  3. If unplugging the MAP sensor causes the voltage to disappear, check that the ground is intact. If it is, then replace the MAP sensor due to internal short.

Jun 17, 2011 | 1995 Cadillac DeVille

1 Answer

When i punch on the gass my 97 tahoe hesitates


usually a bad MAP sensor or TPS. I would test both. Let me know if you have questions and provide test results for repair advice.

MAP Sensor TESTING
See Figures 3, 4 and 5
  1. Backprobe with a high impedance voltmeter at MAP sensor terminals A and C.
  2. With the key ON and engine off, the voltmeter reading should be approximately 5.0 volts.
  3. If the voltage is not as specified, either the wiring to the MAP sensor or the ECM may be faulty. Correct any wiring or ECM faults before continuing test.
  4. Backprobe with the high impotence voltmeter at MAP sensor terminals B and A.
  5. Verify that the sensor voltage is approximately 0.5 volts with the engine not running (at sea level).
  6. Record MAP sensor voltage with the key ON and engine off.
  7. Start the vehicle.
  8. Verify that the sensor voltage is greater than 1.5 volts (above the recorded reading) at idle.
  9. Verify that the sensor voltage increases to approximately 4.5. volts (above the recorded reading) at Wide Open Throttle (WOT).
  10. If the sensor voltage is as specified, the sensor is functioning properly.
  11. If the sensor voltage is not as specified, check the sensor and the sensor vacuum source for a leak or a restriction. If no leaks or restrictions are found, the sensor may be defective and should be replaced.



jturcotte_512.jpg

Fig. Fig. 3: Location of the MAP sensor-TBI system shown


jturcotte_513.jpg

Fig. Fig. 4: Probe the terminals of the MAP sensor to check for proper reference voltage


jturcotte_1792.gif

Fig. Fig. 5: Manifold Absolute Pressure (MAP) sensor wiring diagram








TPS TESTINGSee Figures 2, 3 and 4

  1. Backprobe with a high impedance voltmeter at TPS terminals A and B.
  2. With the key ON and engine off, the voltmeter reading should be approximately 5.0 volts.
  3. If the voltage is not as specified, either the wiring to the TPS or the ECM may be faulty. Correct any wiring or ECM faults before continuing test.
  4. Backprobe with a high impedance voltmeter at terminals C and B.
  5. With the key ON and engine off and the throttle closed, the TPS voltage should be approximately 0.5-1.2 volts.
  6. Verify that the TPS voltage increases or decreases smoothly as the throttle is opened or closed. Make sure to open and close the throttle very slowly in order to detect any abnormalities in the TPS voltage reading.
  7. If the sensor voltage is not as specified, replace the sensor.



jturcotte_514.jpg

Fig. Fig. 2: Using a DVOM, backprobe terminals A and B of the TPS sensor to check for proper reference voltage


jturcotte_515.jpg

Fig. Fig. 3: Using the DVOM, backprobe terminals C and B of the TPS sensor, open and close the throttle and make sure the voltage changes smoothly


jturcotte_1793.gif

Fig. Fig. 4: Throttle Position Sensor (TPS) wiring diagram

May 30, 2011 | Chevrolet Tahoe Cars & Trucks

2 Answers

1992 K1500, code 22, clicking noise from throttle body, will not accelerate properly, changed TPS with no change


OBD Code 22 - Throttle Position Sensor Error (Signal Low)
The Throttle Position sensor signals the Engine Control Module as to the current position of the engine throttle valve. The current throttle valve opening is based on the driver's input from the gas pedal. The ECM uses the information from this sensor to help calculate fuel delivery and spark timing.

Symptoms:
* Extended cranking, possible no-start condition
* Lack of power
* Erratic transmission operation

Common Problems:
* A failed Throttle Position Sensor (TPS) would be the most common causes for code 22
* Testing the TPS circuit would involve checking voltage and ground from the ECM-5v is the normal reading between the ECM reference circuit and the ECM ground circuit at the TPS connector. Checking the TPS signal circuit to the ECM would involve monitoring the TPS signal on a scan tool while jumping the 5v reference and the signal circuits. The TPS reading should go from high when the circuit is "jumpered" to low when the jumper is removed.


Keep us updated.

May 04, 2011 | Chevrolet 1500 Cars & Trucks

1 Answer

Code po105 pops up i had it reset and every 3-4 days it lights back up what does it mean ?


Generic code results from http://www.obd-codes.com/p0105 :

P0105 - MAP Circuit Malfunction

Manifold Absolute Pressure/Barometric Pressure Circuit Malfunction

The MAP (Manifold Absolute Pressure) sensor is part of the fuel management system. It reacts to changes in engine manifold pressure. The PCM (Powertrain Control Module) monitors the MAP sensor continually to properly run the engine. Changes in engine load require changes in the amount of fuel injected, and timing of the ignition system, etc. An engine under load has more manifold pressure(or less vacuum) than an engine that is coasting. As the load changes, the MAP sensor voltage signal to the PCM changes accordingly. To check the MAP sensor operation, though, the PCM watches other sensors to verify that the MAP sensor is working properly.

For example, the PCM compares the TPS (Throttle Position Sensor) signal to the MAP signal to verify the MAP signal isn't "sticking". If the PCM doesn't see a MAP sensor change immediately follow a change in the throttle pedal sensor, it knows there is a problem with the MAP sensor and sets P0105. Or, if the PCM notices that the TPS indicates the engine is under load, but the MAP signal indicates that the engine is "coasting" it, again, knows there is a problem with the MAP sensor or TPS and sets P0105.

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Symptoms of a P0105 check engine light code may include:

  • Poor running engine
  • Engine runs rich
  • Engine won't idle
  • Engine backfires through tailpipe
  • Engine misfire under load or at idle
  • MIL (Malfunction Indicator Lamp) illumination
  • In some extreme cases there may be no symptoms other than MIL illumination

A P0105 DTC could be caused by:

  • MAP sensor vacuum hose disconnected or plugged
  • Bad MAP sensor
  • Bad TPS
  • Damaged or problematic MAP sensor connector
  • Damaged or problematic TPS connector
  • Damaged wiring
  • Short to reference voltage on signal circuit of MAP sensor
  • Loss of ground to MAP sensor or TPS
  • Open on signal circuit of MAP sensor
  • Bad PCM

Using a scanner or code reader, turn the ignition on and engine OFF; what does the MAP sensor voltage read? It should be about 4 Volts for sea level. If you are at a higher altitude, it should decrease about half a volt or so for each 1,000 ft. of altitude (this will vary from model to model) Or if you have a separate MAF (Mass air flow) sensor on your vehicle, they are usually equipped with a Barometric pressure reading. If so, the Baro reading should match the MAP reading (they both measure ambient air pressure). If they're roughly equal, then, check for Freeze Frame data of the MAP sensor (if available).

NOTE: Freeze Frame data is the PCM recording a fault when it happens. It captures the readings of the various PIDS (parameter identifiers)available to troubleshoot what happened. It's like a recording of the problem as it happened. At idle a typical MAP sensor Voltage reading should be about a volt, and at WOT (wide open throttle) it should approach 4.5 to 5 Volts. As for the TPS, at idle, the voltage reading is about 1 Volt or less. As the throttle is opened the reading will increase to 4.5 Volts at WOT. Do the two readings make sense? For example, if the TPS reading on Freeze Frame data shows 2.5 Volts (indicating partial throttle) does the MAP sensor indicate a reading that isn't at either extreme? Using the Freeze Frame data (if available) compare the MAP reading to the TPS when the problem occurred. This can help you identify what happened

If you have no access to Freeze Frame data then check if the MAP sensor voltage changes when you apply vacuum to it. You can do this by mouth or a vacuum pump. The voltage should increase as you apply vacuum. If the reading doesn't change as you apply vacuum, make sure there are no obstructions in the hose to the sensor. If the hose is clear, the MAP sensor is usually bad, but it doesn't rule out the following from causing the problem: Does the MAP sensor appear to be stuck at less than .5 Volts? Then:

NOTE: This code shouldn't set if the MAP is stuck at extremely low voltage, however, I'm adding it in because there's no way to know for certain for which vehicles a low voltage condition may set a P0105.

  1. Inspect the wiring harness and MAP sensor connector. Repair any damage
  2. Unplug the MAP sensor connector. Also, at the PCM connector, remove the MAP sensor signal wire and check for continuity to the MAP sensor connector. If there is infinite resistance, then repair open in MAP signal circuit. If the signal wire has continuity to the MAP sensor connector, then check for 5 volt reference voltage to the connector and a good ground. If both are present, then re-install all removed wiring and replace the MAP sensor.

Does the MAP sensor appear to be stuck at full 4.5 voltage? Then:

  1. Inspect the wiring harness for damage. Repair as needed
  2. Remove the MAP sensor signal wire from the PCM connector. With a voltmeter measure the voltage with KEY ON ENGINE OFF. Is there 4.5 Volts? If so, unplug the MAP sensor and recheck. If it is still present, then repair short between the signal wire and 5 volt reference wire.
  3. If unplugging the MAP sensor causes the voltage to disappear, check that the ground is intact. If it is, then replace the MAP sensor due to internal short.

Feb 27, 2011 | Jaguar X-Type Cars & Trucks

1 Answer

I have this eobd code problem p0105 in my elantra, where those sensors?


P0105 - Manifold Absolute Pressure/Barometric Pressure Circuit Malfunction
The MAP (Manifold Absolute Pressure) sensor is part of the fuel management system. It reacts to changes in engine manifold pressure. The PCM (Powertrain Control Module) monitors the MAP sensor continually to properly run the engine. Changes in engine load require changes in the amount of fuel injected, and timing of the ignition system, etc. An engine under load has more manifold pressure(or less vacuum) than an engine that is coasting. As the load changes, the MAP sensor voltage signal to the PCM changes accordingly. To check the MAP sensor operation, though, the PCM watches other sensors to verify that the MAP sensor is working properly.

For example, the PCM compares the TPS (Throttle Position Sensor) signal to the MAP signal to verify the MAP signal isn't "sticking". If the PCM doesn't see a MAP sensor change immediately follow a change in the throttle pedal sensor, it knows there is a problem with the MAP sensor and sets P0105. Or, if the PCM notices that the TPS indicates the engine is under load, but the MAP signal indicates that the engine is "coasting" it, again, knows there is a problem with the MAP sensor or TPS and sets P0105.

Symptoms of a P0105 check engine light code may include:
* Poor running engine
* Engine runs rich
* Engine won't idle
* Engine backfires through tailpipe
* Engine misfire under load or at idle
* MIL (Malfunction Indicator Lamp) illumination
* In some extreme cases there may be no symptoms other than MIL illumination

Causes: A P0105 DTC could be caused by:
* MAP sensor vacuum hose disconnected or plugged
* Bad MAP sensor
* Bad TPS
* Damaged or problematic MAP sensor connector
* Damaged or problematic TPS connector
* Damaged wiring
* Short to reference voltage on signal circuit of MAP sensor
* Loss of ground to MAP sensor or TPS
* Open on signal circuit of MAP sensor
* Bad PCM

Possible Solutions:
Using a scanner or code reader, turn the ignition on and engine OFF; what does the MAP sensor voltage read? It should be about 4 Volts for sea level. If you are at a higher altitude, it should decrease about half a volt or so for each 1,000 ft. of altitude (this will vary from model to model) Or if you have a separate MAF (Mass air flow) sensor on your vehicle, they are usually equipped with a Barometric pressure reading. If so, the Baro reading should match the MAP reading (they both measure ambient air pressure). If they're roughly equal, then, check for Freeze Frame data of the MAP sensor (if available).

NOTE: Freeze Frame data is the PCM recording a fault when it happens. It captures the readings of the various PIDS (parameter identifiers)available to troubleshoot what happened. It's like a recording of the problem as it happened. At idle a typical MAP sensor Voltage reading should be about a volt, and at WOT (wide open throttle) it should approach 4.5 to 5 Volts. As for the TPS, at idle, the voltage reading is about 1 Volt or less. As the throttle is opened the reading will increase to 4.5 Volts at WOT. Do the two readings make sense? For example, if the TPS reading on Freeze Frame data shows 2.5 Volts (indicating partial throttle) does the MAP sensor indicate a reading that isn't at either extreme? Using the Freeze Frame data (if available) compare the MAP reading to the TPS when the problem occurred. This can help you identify what happened

If you have no access to Freeze Frame data then check if the MAP sensor voltage changes when you apply vacuum to it. You can do this by mouth or a vacuum pump. The voltage should increase as you apply vacuum. If the reading doesn't change as you apply vacuum, make sure there are no obstructions in the hose to the sensor. If the hose is clear, the MAP sensor is usually bad, but it doesn't rule out the following from causing the problem: Does the MAP sensor appear to be stuck at less than .5 Volts? Then:

NOTE: This code shouldn't set if the MAP is stuck at extremely low voltage, however, I'm adding it in because there's no way to know for certain for which vehicles a low voltage condition may set a P0105.

1. Inspect the wiring harness and MAP sensor connector. Repair any damage
2. Unplug the MAP sensor connector. Also, at the PCM connector, remove the MAP sensor signal wire and check for continuity to the MAP sensor connector. If there is infinite resistance, then repair open in MAP signal circuit. If the signal wire has continuity to the MAP sensor connector, then check for 5 volt reference voltage to the connector and a good ground. If both are present, then re-install all removed wiring and replace the MAP sensor.

Does the MAP sensor appear to be stuck at full 4.5 voltage? Then:
1. Inspect the wiring harness for damage. Repair as needed
2. Remove the MAP sensor signal wire from the PCM connector. With a voltmeter measure the voltage with KEY ON ENGINE OFF. Is there 4.5 Volts? If so, unplug the MAP sensor and recheck. If it is still present, then repair short between the signal wire and 5 volt reference wire.
3. If unplugging the MAP sensor causes the voltage to disappear, check that the ground is intact. If it is, then replace the MAP sensor due to internal short.

MAP sensor codes include P0106, P0107, P0108 and P0109 .


LOCATIONS:
Manifold Absolute Pressure (MAP) Sensor: The MAP sensor is located against the firewall to the left side of the engine.
Barometric Pressure Sensor: This sensor is installed on the VAF sensor; Volume Air Flow Sensor Is located in the air intake plenum assembly.

Hope this helps.

Jan 24, 2011 | 2001 Hyundai Elantra

1 Answer

I have a 91 s10 chevy, and lately i have been having problems with the way it has been running on warm up. When i fire it up it spuders and dies right away. But will run fine after it is warm? i dont know...


Hi there sounds like idle air control valve failure. Or also known as fast idle valve. I would suggest locate and clean. If that doesn't help then replace it and you should be good to go

Nov 04, 2017 | 1991 Chevrolet S-10

1 Answer

I have a p0105 error. They say this is a dirty body throttle. How can I clean this myself? My car is a 2002 Chevy Envoy.


DTC P0105 - Crankshaft Position Sensor B Circuit Malfunction or Manifold Absolute Pressure/Barometric Pressure Circuit Malfunction


What does that mean?
The MAP (Manifold Absolute Pressure) sensor is part of the fuel management system. It reacts to changes in engine manifold pressure. The PCM (Powertrain Control Module) monitors the MAP sensor continually to properly run the engine. Changes in engine load require changes in the amount of fuel injected, and timing of the ignition system, etc. An engine under load has more manifold pressure(or less vacuum) than an engine that is coasting. As the load changes, the MAP sensor voltage signal to the PCM changes accordingly. To check the MAP sensor operation, though, the PCM watches other sensors to verify that the MAP sensor is working properly.

For example, the PCM compares the TPS (Throttle Position Sensor) signal to the MAP signal to verify the MAP signal isn't "sticking". If the PCM doesn't see a MAP sensor change immediately follow a change in the throttle pedal sensor, it knows there is a problem with the MAP sensor and sets P0105. Or, if the PCM notices that the TPS indicates the engine is under load, but the MAP signal indicates that the engine is "coasting" it, again, knows there is a problem with the MAP sensor or TPS and sets P0105.

Symptoms: Symptoms of a P0105 check engine light code may include:
* Poor running engine
* Engine runs rich
* Engine won't idle
* Engine backfires through tailpipe
* Engine misfire under load or at idle
* MIL (Malfunction Indicator Lamp) illumination
* In some extreme cases there may be no symptoms other than MIL illumination

Causes: A P0105 DTC could be caused by:
* MAP sensor vacuum hose disconnected or plugged
* Bad MAP sensor
* Bad TPS
* Damaged or problematic MAP sensor connector
* Damaged or problematic TPS connector
* Damaged wiring
* Short to reference voltage on signal circuit of MAP sensor
* Loss of ground to MAP sensor or TPS
* Open on signal circuit of MAP sensor
* Bad PCM

Possible Solutions: Using a scanner or code reader, turn the ignition on and engine OFF; what does the MAP sensor voltage read? It should be about 4 Volts for sea level. If you are at a higher altitude, it should decrease about half a volt or so for each 1,000 ft. of altitude (this will vary from model to model) Or if you have a separate MAF (Mass air flow) sensor on your vehicle, they are usually equipped with a Barometric pressure reading. If so, the Baro reading should match the MAP reading (they both measure ambient air pressure). If they're roughly equal, then, check for Freeze Frame data of the MAP sensor (if available).

NOTE: Freeze Frame data is the PCM recording a fault when it happens. It captures the readings of the various PIDS (parameter identifiers)available to troubleshoot what happened. It's like a recording of the problem as it happened. At idle a typical MAP sensor Voltage reading should be about a volt, and at WOT (wide open throttle) it should approach 4.5 to 5 Volts. As for the TPS, at idle, the voltage reading is about 1 Volt or less. As the throttle is opened the reading will increase to 4.5 Volts at WOT. Do the two readings make sense? For example, if the TPS reading on Freeze Frame data shows 2.5 Volts (indicating partial throttle) does the MAP sensor indicate a reading that isn't at either extreme? Using the Freeze Frame data (if available) compare the MAP reading to the TPS when the problem occurred. This can help you identify what happened

If you have no access to Freeze Frame data then check if the MAP sensor voltage changes when you apply vacuum to it. You can do this by mouth or a vacuum pump. The voltage should increase as you apply vacuum. If the reading doesn't change as you apply vacuum, make sure there are no obstructions in the hose to the sensor. If the hose is clear, the MAP sensor is usually bad, but it doesn't rule out the following from causing the problem: Does the MAP sensor appear to be stuck at less than .5 Volts? Then:

NOTE: This code shouldn't set if the MAP is stuck at extremely low voltage, however, I'm adding it in because there's no way to know for certain for which vehicles a low voltage condition may set a P0105.

1. Inspect the wiring harness and MAP sensor connector. Repair any damage
2. Unplug the MAP sensor connector. Also, at the PCM connector, remove the MAP sensor signal wire and check for continuity to the MAP sensor connector. If there is infinite resistance, then repair open in MAP signal circuit. If the signal wire has continuity to the MAP sensor connector, then check for 5 volt reference voltage to the connector and a good ground. If both are present, then re-install all removed wiring and replace the MAP sensor.

Does the MAP sensor appear to be stuck at full 4.5 voltage? Then:

1. Inspect the wiring harness for damage. Repair as needed
2. Remove the MAP sensor signal wire from the PCM connector. With a voltmeter measure the voltage with KEY ON ENGINE OFF. Is there 4.5 Volts? If so, unplug the MAP sensor and recheck. If it is still present, then repair short between the signal wire and 5 volt reference wire.
3. If unplugging the MAP sensor causes the voltage to disappear, check that the ground is intact. If it is, then replace the MAP sensor due to internal short.

MAP sensor codes include P0105, P0106, P0107, P0108 and P0109 .


Hope helps (remember rated this).

Jul 09, 2010 | 2002 GMC Envoy

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