Question about 2000 Chevrolet Astro

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P0121 code, 2000 chevy astro

Replaced tps, changed out pcm, checked all wiring....code still resets at 48 mph

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Given that you have replaced the TPS and the PCM, the next step would be to check the connector itself and make sure it is making a good connection and there are no corrosion or anything like that on the connector.

After that, ensure that the TPS has the correct voltage to it, usually its around 5vdc, it should never have full batter voltage to it (12vdc). The PCM usually supplies both the 5vdc reference and the ground for the TPS. Its also entirely possible that (depending on where you bought the TPS) that you were given the wrong one for your vehicle. Not a common thing, but it could happen.

The code will be set if the PCM sees a TPS angle that is not consistent with the RPMs of the engine. If you are having any shifting issues such as hard shifts or the engine having to rev higher to shift, that usually a clear indication there is still something wrong with the TPS circuit even if the TPS itself is good.

Hope this helps.

Posted on Dec 31, 2008

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98 volvo glt. TPS


When you turn the vehicle on the PCM does a check on the system. For most sensors, it checks power and ground. Turns the light off if all is good. Since yours comes on after a few seconds, you need to check the signal return wire. Wires tend to break right at the plug. You'll need a volt/ohmmeter to check it. Also check the continuity of the wire from the TPS to the PCM. Anything over 5 ohms needs replaced. I just cut the wire and run a new one.

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Still not winning wi th the Durango. had it scanned still brings up tps.i know it could be bad although it's new.so i changed a couple coils .oem coils but still no luck.i really don't want to take in


If still having TPS codes after sensor replacement you will have to check the wiring at the sensor for 5v reference ground and signal return to PCM. If any are missing, the code will reset and it will not run properly

Jul 12, 2015 | Cars & Trucks

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Smog Filed due to error P0121 Throttle/Pedal Position Sensor/Switch A Circuit range/performance.


Replacing TPS will reset the light but will stay in memory until the computer is reset. For help to change throttle body sensor check out you tube :How To Install Replace Throttle Position Sensor Chevy Silverado GMC Sierra.

Mar 23, 2015 | 2007 Chevrolet Silverado 1500 2WD

1 Answer

I need to know the code po120


Throttle Position Sensor/Switch (TPS) A Circuit Malfunction
The TPS (Throttle Position Sensor) is a potentiometer that is mounted to the throttle body. It detects the throttle blade angle. As the throttle blade moves, the TPS sends a signal to the PCM (Powertrain Control Module). Usually a three wire sensor: A 5 volt reference from the PCM to the TPS, a ground from the PCM to the TPS, and a signal return from the TPS to the PCM. The TPS sends the throttle position information back to the PCM on this signal wire. When the throttle is closed the signal is near .45 volts. At WOT (Wide Open Throttle) the TPS signal voltage will approach a full 5 volts. When the PCM sees a voltage that is outside of normal operating range, P0120 will set. NOTE: The PCM knows that any large change in throttle position means a cooresponding change in manifold pressure (MAP). On some models the PCM will monitor MAP and TPS operation for comparison. Meaning that if the PCM sees a large percentage change in throttle position, it expects to see a cooresponding change in manifold pressure and vice versa. If it doesn't see this comparitive change, P0120 may set.

Dec 11, 2014 | 2001 Toyota Sienna

1 Answer

I have a Volvo v70 2.4T that sometimes runs fine but is off the road now because on a regular bases runs lumpy, smells like rich mix, sometimes burny smell from exhaust then goes into 'performance...


Throttle Position Sensor/Switch A Circuit Range/Performance Problem


What does that mean?


The Throttle position sensor is a potentiometer that measures the amount of throttle opening. As the throttle is opened, the reading (measured in volts) goes up. The powertrain control module (PCM) supplies a 5 Volt reference signal to the throttle position sensor (TPS) and usually a ground also. A general measurement is: at idle = .5 Volts; full throttle = 4.5 Volts. If the PCM detects that the throttle angle is greater or less than it should be for a specific RPM, it will set this code.


Potential Symptoms


Symptoms of a P0121 trouble code could include:


Malfunction Indicator Lamp (MIL) illumination (Check Engine Light or Service Engine Soon light)
Intermittent stumble on acceleration or deceleration
Blows black smoke on acceleration
No start
Causes


A code P0121 may mean that one or more of the following has happened:


TPS has intermittent open or short internally
Harness is rubbing and causing an open or short in the wiring
Bad connection at the TPS
Bad PCM (less likely)
Water or corrosion in connector or sensor
Possible Solutions


1. If you have access to a scan tool, see what the idle and WOT (wide open throttle) readings are for the TPS. Check if they're close to the specifications mentioned above. If not, then replace the TPS and re-check.


2. Check for an intermittent open or short in the TPS signal. To do that, you can't use a scan tool. You'll need an oscilliscope. The reason is because scan tools take samplings of many different readings over just one or two data lines and can miss an intermittent drop out. Hook up your oscilliscope and watch the signal. It should sweep up and down smoothly with no drop outs or spikes.


3. If no problems were noticed, perform a wiggle test. Do this by wiggling the connector and harness while watching the pattern. Does it drop out? If so, replace TPS and re-check.


4. If you have no TPS signal, check for 5 Volt reference at the connector. If it's present, check the ground circuit for open or shorts.


5. Make sure the signal circuit isn't 12V. It should never have battery voltage. If it does, trace circuit for short to voltage and repair.


6. Look for any water in the connector and replace TPS as necessary.

Nov 20, 2012 | Cars & Trucks

2 Answers

Keep getting OBD code P0121 on my 98 grand prix GTP


Hi there:

DTC P0121 - Throttle Position Sensor/Switch A Circuit Range/Performance Problem


The Throttle position sensor is a potentiometer that measures the amount of throttle opening. As the throttle is opened, the reading (measured in volts) goes up. The powertrain control module (PCM) supplies a 5 Volt reference signal to the throttle position sensor (TPS) and usually a ground also. A general measurement is: at idle = .5 Volts; full throttle = 4.5 Volts. If the PCM detects that the throttle angle is greater or less than it should be for a specific RPM, it will set this code.





Symptoms of a P0121 trouble code could include:
* Malfunction Indicator Lamp (MIL) illumination (Check Engine Light or Service Engine Soon light)
* Intermittent stumble on acceleration or deceleration
* Blows black smoke on acceleration
* No start




A code P0121 may mean that one or more of the following has happened:
* TPS has intermittent open or short internally
* Harness is rubbing and causing an open or short in the wiring
* Bad connection at the TPS
* Bad PCM (less likely)
* Water or corrosion in connector or sensor





Possible Solutions:
1. If you have access to a scan tool, see what the idle and WOT (wide open throttle) readings are for the TPS. Check if they're close to the specifications mentioned above. If not, then replace the TPS and re-check.
2. Check for an intermittent open or short in the TPS signal. To do that, you can't use a scan tool. You'll need an oscilliscope. The reason is because scan tools take samplings of many different readings over just one or two data lines and can miss an intermittent drop out. Hook up your oscilliscope and watch the signal. It should sweep up and down smoothly with no drop outs or spikes.
3. If no problems were noticed, perform a wiggle test. Do this by wiggling the connector and harness while watching the pattern. Does it drop out? If so, replace TPS and re-check.
4. If you have no TPS signal, check for 5 Volt reference at the connector. If it's present, check the ground circuit for open or shorts.
5. Make sure the signal circuit isn't 12V. It should never have battery voltage. If it does, trace circuit for short to voltage and repair.
6. Look for any water in the connector and replace TPS as necessary.


Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa, have a nice day.

Jun 20, 2012 | 1998 Pontiac Grand Prix

1 Answer

03 caravan showing codesP0123 and P0121. Can anyone help me with this. The van is not shifting gears properly. Thanks!


Hi there:
P0121 - Throttle Position Sensor/Switch A Circuit Range/Performance

The Throttle position sensor is a potentiometer that measures the amount of throttle opening. As the throttle is opened, the reading (measured in volts) goes up. The powertrain control module (PCM) supplies a 5 Volt reference signal to the throttle position sensor (TPS) and usually a ground also. A general measurement is: at idle = .5 Volts; full throttle = 4.5 Volts. If the PCM detects that the throttle angle is greater or less than it should be for a specific RPM, it will set this code.


Symptoms of a P0121 trouble code could include:

Malfunction Indicator Lamp (MIL) illumination (Check Engine Light or Service Engine Soon light)
Intermittent stumble on acceleration or deceleration
Blows black smoke on acceleration
No start


A code P0121 may mean that one or more of the following has happened:
TPS has intermittent open or short internally
Harness is rubbing and causing an open or short in the wiring
Bad connection at the TPS
Bad PCM (less likely)
Water or corrosion in connector or sensor

Possible Solutions:
1. If you have access to a scan tool, see what the idle and WOT (wide open throttle) readings are for the TPS. Check if they're close to the specifications mentioned above. If not, then replace the TPS and re-check.

2. Check for an intermittent open or short in the TPS signal. To do that, you can't use a scan tool. You'll need an oscilliscope. The reason is because scan tools take samplings of many different readings over just one or two data lines and can miss an intermittent drop out. Hook up your oscilliscope and watch the signal. It should sweep up and down smoothly with no drop outs or spikes.

3. If no problems were noticed, perform a wiggle test. Do this by wiggling the connector and harness while watching the pattern. Does it drop out? If so, replace TPS and re-check.

4. If you have no TPS signal, check for 5 Volt reference at the connector. If it's present, check the ground circuit for open or shorts.

5. Make sure the signal circuit isn't 12V. It should never have battery voltage. If it does, trace circuit for short to voltage and repair.

6. Look for any water in the connector and replace TPS as necessary.


P0123 Code - Throttle Position Sensor/Switch A Circuit High Input
A P0123 code means that the the car's computer has detected that the TPS (throttle position sensor) is reporting too high a voltage.


Symptoms may include:
Rough idle
High idle
Surging
other symptoms may also be present


A code P0123 may mean that one or more of the following has happened:
TPS not mounted securely
TPS circuit short to ground or another wire
Faulty TPS
Damaged computer (PCM)

Possible Solutions
If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.

If there are symptoms such as the engine is stumbling or hesitating, carefully inspect all wiring and connectors that lead to the TPS. More than likely the problem is with the TPS wiring. Check the voltage at the TPS (refer to a service manual for your vehicle for this specific information). If the voltage spikes or is too high (over 4.65 volts with key on, engine off), then that is indicative of a problem. Carefully trace each wire from the TPS wiring harness to check for breaks, rubbing against other components, etc.


Hope helps

Apr 19, 2012 | 2003 Dodge Caravan

1 Answer

Tdc po121


Hi there:
DTC P0121 - Throttle Position Sensor/Switch A Circuit Range/Performance Problem.
The Throttle position sensor is a potentiometer that measures the amount of throttle opening. As the throttle is opened, the reading (measured in volts) goes up. The powertrain control module (PCM) supplies a 5 Volt reference signal to the throttle position sensor (TPS) and usually a ground also. A general measurement is: at idle = .5 Volts; full throttle = 4.5 Volts. If the PCM detects that the throttle angle is greater or less than it should be for a specific RPM, it will set this code.

Symptoms of a P0121 trouble code could include:
Malfunction Indicator Lamp (MIL) illumination (Check Engine Light or Service Engine Soon light)
Intermittent stumble on acceleration or deceleration
Blows black smoke on acceleration
No start

A code P0121 may mean that one or more of the following has happened:
TPS has intermittent open or short internally
Harness is rubbing and causing an open or short in the wiring
Bad connection at the TPS
Bad PCM (less likely)
Water or corrosion in connector or sensor

Possible Solutions:
1. If you have access to a scan tool, see what the idle and WOT (wide open throttle) readings are for the TPS. Check if they're close to the specifications mentioned above. If not, then replace the TPS and re-check.
2. Check for an intermittent open or short in the TPS signal. To do that, you can't use a scan tool. You'll need an oscilliscope. The reason is because scan tools take samplings of many different readings over just one or two data lines and can miss an intermittent drop out. Hook up your oscilliscope and watch the signal. It should sweep up and down smoothly with no drop outs or spikes.
3. If no problems were noticed, perform a wiggle test. Do this by wiggling the connector and harness while watching the pattern. Does it drop out? If so, replace TPS and re-check.
4. If you have no TPS signal, check for 5 Volt reference at the connector. If it's present, check the ground circuit for open or shorts.
5. Make sure the signal circuit isn't 12V. It should never have battery voltage. If it does, trace circuit for short to voltage and repair.
6. Look for any water in the connector and replace TPS as necessary.

Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa, have a nice day.

Feb 23, 2012 | 2007 Chevrolet Malibu Maxx LTZ Hatchback

1 Answer

2004 jeep grand Cherokee 4.7 ltr ho code p0121


DTC P0121 - Throttle Position Sensor/Switch A Circuit Range/Performance Problem
The Throttle position sensor is a potentiometer that measures the amount of throttle opening. As the throttle is opened, the reading (measured in volts) goes up. The powertrain control module (PCM) supplies a 5 Volt reference signal to the throttle position sensor (TPS) and usually a ground also. A general measurement is: at idle = .5 Volts; full throttle = 4.5 Volts. If the PCM detects that the throttle angle is greater or less than it should be for a specific RPM, it will set this code.

Symptoms of a P0121 trouble code could include:
Malfunction Indicator Lamp (MIL) illumination (Check Engine Light or Service Engine Soon light)
Intermittent stumble on acceleration or deceleration
Blows black smoke on acceleration
No start

A code P0121 may mean that one or more of the following has happened:
TPS has intermittent open or short internally
Harness is rubbing and causing an open or short in the wiring
Bad connection at the TPS
Bad PCM (less likely)
Water or corrosion in connector or sensor

Possible Solutions:
1. If you have access to a scan tool, see what the idle and WOT (wide open throttle) readings are for the TPS. Check if they're close to the specifications mentioned above. If not, then replace the TPS and re-check.

2. Check for an intermittent open or short in the TPS signal. To do that, you can't use a scan tool. You'll need an oscilliscope. The reason is because scan tools take samplings of many different readings over just one or two data lines and can miss an intermittent drop out. Hook up your oscilliscope and watch the signal. It should sweep up and down smoothly with no drop outs or spikes.

3. If no problems were noticed, perform a wiggle test. Do this by wiggling the connector and harness while watching the pattern. Does it drop out? If so, replace TPS and re-check.

4. If you have no TPS signal, check for 5 Volt reference at the connector. If it's present, check the ground circuit for open or shorts.

5. Make sure the signal circuit isn't 12V. It should never have battery voltage. If it does, trace circuit for short to voltage and repair.

6. Look for any water in the connector and replace TPS as necessary.


Hope ths helps; keep us updated.

Sep 20, 2011 | 2004 Jeep Grand Cherokee

1 Answer

Changed the TPS on my 05 sedona and it reads P0122 code on scanner, after clearing the codes the check engine light wont turn off and the codes still reads P0122, maybe a bad TPS ?


this code may cause by:

TPS not mounted securely.

TPS circuit short to ground or another wire.

Faulty TPS.

Damaged computer (PCM).

to fix this code you can try this:


Carefully check the throttle position sensor (TPS), wiring connector, and wiring for breaks, etc. Repair or replace as necessary
Check the voltage at the TPS (refer to a service manual for your vehicle for specific information). If the voltage is too low that is indicative of a problem. Replace if necessary.
If recently replaced the TPS may need to be adjusted. On some vehicles the installation instructions call for the TPS to be properly aligned or adjusted, consult a repair manual for specifics.
If there are no symptoms at all, the problem may be intermittent and clearing the code may resolve the issue temporarily. If this is the case then you should definitely check the wiring to be sure it's not rubbing on anything, grounding, etc. The code may come back.

Aug 02, 2011 | 2005 Kia Sedona

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