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How to clean a throttle body on a 2002 envoy - 2002 GMC Envoy

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Posted on Jan 02, 2017

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SOURCE: Wanting to stall at all speeds

It sounds like a electrical problem to me. Like the ignition control module. It can be tested at your local auto parts stores.

Posted on Oct 17, 2008

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SOURCE: I have a p0105 error. They say this is a dirty

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).

Posted on Jul 13, 2010

  • 21873 Answers

SOURCE: 2002 gmc envoy stalls when turning and slowing down

I am going to assume the check engine light is not on.
I would check the throttle body to see if it needs to be cleaned, and check the idle air control valve to see if it is working. The computer controls idle speed by the amount of air coming into the throttle body.
The ac problem is probably something different such as low freon or a cooling fan problem.

Posted on Sep 12, 2012

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I have a 2002 GMC Envoy, the idle goes up/down & wants to die out when using the defrost/fan during the start up/idle. Is it a vacuum line somewhere?

Common problem after the battery is unhooked or replaced. You'll get the same results if you turn the AC on also...Unhook the battery, clean your throttle body, with throttle body cleaner (Seafoam works good) with only a rag or plastic bristled brush, no metal as it will scratch it. I prefer to remove the throttle body (4 bolts) to clean both sides, you CAN reuse the hard plastic gasket. When finished, hook the battery back up and drive around for 15 min or so (with no defrost or AC on,everything off), for the computer to relearn the newly cleaned TB. Your problem will be solved for about $8 if you do it yourself.

Oct 16, 2014 | 2002 GMC Envoy

1 Answer

Truck shuts off only when you turn on defrost

The throttle body needs to be cleaned, grime in this area prevents the throttle plate from closing completely and allowing air to enter, making the air/fuel mixture lean. Make sure to clean the front and back sides of the throttle body. Also, disconnect the battery during the cleaning process to allow the computer to reset and relearn to the cleaned throttle body.

Oct 02, 2012 | 2002 GMC Envoy

1 Answer

2002 envoy engine stumbling

Try cleaning the throttle body first. Make sure to clean both the front side and rear side thoroughly. Also, disconnect the battery while doing the cleaning, this will reset the computer and allow it to relearn to the cleaned throttle body.
Unless you have the check engine light on and can retrieve a fault code, do not start to change parts. With the mileage you have, you may want to change the O2 sensors.

Nov 13, 2011 | 2002 GMC Envoy

1 Answer

I have a 2002 gmc envoy with 4.2 i 6 with 65k the reduce engine power light came on, and it would only go about 10 mph. After it sat a day or so it ran go for about a week then it did it the...

Sounds like your throttle body is sticking. Common problem, the reduced power is just a safe mode. 1st disconnect your battery, then clean your throttle body with throttle body cleaner. When finished, connect the battery back up. Turn off all accessoried and drive around for 20 minutes or so, for the computer to relearn a properly functioning throttle body. Should solve your problem, and if you do it yourself, will cost you around $5 for the can of TB cleaner.

Apr 26, 2011 | 2002 GMC Envoy

1 Answer

Reduce engine light came on in my 2002 envoy and it feel as if the truck is not getting any power, why is that? the truck slowed down so i pulled over cut it off an started it back up. after starting back...

Reduced engine power is just like a safe mode. First things first, clean your throttle body. It's possible the butterfly is sticking. Disconnect the battery, clean your throttle body with throttle body cleaner, must be nice and shiny. When finished, drive around for 20 minutes or so with all accessories off. This will allow the computer to relearn a properly functioning throttle body.

Mar 25, 2011 | 2002 GMC Envoy

1 Answer

Recently i replaced battery in my 2002 envoy, now if a/c is on it idles rough and will stall, can you help me with solving this problem

Clean your throttle body. Disconnect the battery, and take the plastic resonator and large hoses off that attach to the throttle body. Clean with throttle body cleaner, must be nice and shiny. When finished, drive around for 20 min or so, so the computer can re-learn the properly functioning throttle body. Your computer learned some bad habits with the dirty throttle body, so when you disconnect the battery and reconnect it, it thinks the throttle body is clean and functioning properly which is not the case. If you do it yourself, can cost you a can of throttle body cleaner $7.

Feb 19, 2011 | 2002 GMC Envoy

1 Answer

Hello my name is fernando i have a 2002 gmc envoy im having a problem with my car took it to shop and they cant find the problem wen i turn on heater or ac the car idles up and down then turns off as long...

Easy one. Probably does this with either your A/C on, and OR your de-froster. The de-froster uses the A/C to dry the air. You must of either put a new battery in recently or disconnected it. Clean your throttle body with throttle body cleaner while the battery is disconnected. When finished drive around for 20 minutes or so with all accessories off. At this point your computer will re-learn a properly functioning throttle body. Your computer learned some bad habits with that dirty throttle body, so when the battery was disconnected for one reason or another, it thinks the throttle body should be functioning properly, which it is not. I'd find a new mechanic, this is a very very common problem with Envoys and Trailblazers. If you decide to do it yourself, it will cost you just a bottle of throttle body cleaner, about $7.

Feb 15, 2011 | 2002 GMC Envoy

1 Answer

2002 envoy battery died - replaced and now wont start on Driver 2 and wants to stall at all stops on Driver 1 - also stalls when the air conditioner is used

Very common problem with Envoys and Trailblazers. For Driver 1 Clean your throttle body with throttle body cleaner while the battery is disconnected. After this is done, re-connect your battery, drive around for 5-10 miles while the computer resets and relearns. Do the driving with the A/C off and the defroster off. Your problem will be solved. I've never heard of not starting in a different driver mode with just changing the battery.

Dec 10, 2010 | 2002 GMC Envoy

1 Answer

My 2002 gmc envoy stalls when i turn on the ac

The throttle body needs cleaning, the butterfly and surrounding area has built up deposits that prevent the butterfly from closing all the way. Visit and search for throttle body cleaning.

Aug 09, 2010 | 2002 GMC Envoy

1 Answer

2002 ENVOY

I'd concentrate on IAC (idle air control,)motor, or AIS (automatic idle speed) motor. I believe on your vehicle, it's probably referred to as IAC motor, but either way, same thing, they control your idle during load conditions such as your experiencing. Have had good luck just removing it & cleaning the pintle on it & port (hole) that it comes out of with throttle body cleaner spray. If it cures it for a while, then starts to act up again, replace it. Should be mounted at front/side area of throttle body. be careful not to damage, or lose, "O'" ring at the base of where it mounts to throttle body. If you look the part up online at autozone, or pep boys, you'll know what to look for if not familiar with it.

Mar 09, 2009 | 2002 GMC Envoy

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