Rick's Free Auto Repair Advice » GM Vehicles

Buick Park Avenue headlights stay on

Rick — Mon, 19 Apr 2010 22:18:03 +0000

Shops are reporting a problem with the GM “twilight sentinel” system on Buick Park Avenue vehicles. Owners report that the headlights will not turn off.

Start your diagnostics by unplugging the head lamp switch connector from the switch. If the headlights now go out, replace the head lamp switch.

Get a new headlight switch from Amazon.com. Standard Motor Parts #DS717 fits Buick Park Ave & Park Ave Ultra from 1997-2005

If the lights do not go out, check the white wire at the lamp driver module (located under the center of the instrument panel) for a short to ground pin J and pin B1. If the white wire is not shorted, the problem is in the lamp control module. Replace it.

For more information on this repair or any others for your vehicle, buy an online subscription to either Alldatadiy.com or eautorepair.net. Click on this link to compare the two services: Compare Alldata and Eautorepair.

If you just need information for a single repair and want to save money,eautorepair offers a lower price 1-week subscription for only $11.99. Or, if you'll be working on this vehicle in the future, you can buy a 1-year subscription (Alldatadiy.com for $26.99, or eautorepair.net $29.99)

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ABS light on GM vehicles

Rick — Fri, 16 Apr 2010 17:17:57 +0000

GM has issued a TSB #04-05-025-002A covering the following vehicles:
2004 Buick Rainier
2002-04 Cadillac Escalade, Escalade EXT
2003-04 Chevrolet Silverado
2000-04 Chevrolet Suburban, Tahoe
2003-04 Chevrolet Avalanche, Trailblazer
2003-04 Chevrolet SSR
1999-04 GMC Sierra
2000-04 GMC Yukon, Yukon Denali, Yukon XL
2002-04 GMC Envoy
2004 GMC Envoy XUV
2002-2004 Oldsmobile Bravada

The problem shows up as a glowing ABS light and trouble coded C0265, C0201, U1041 and a loss of communication with the brake module (EBCM). The TSB warns dealers NOT to replace the EBCM. The problem is a bad ground. Refer to a wiring diagram to find the grounding location for your vehicle. Then clean the ground area and spray it with rubberized undercoating.

For midsized utility vehicles, find the location of ground #304
For Chevrolet SSR, find the location for ground #400
For full-size trucks and utilities, find the location for ground #110

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Hover your mouse over the REPAIR ARTICLES tab at the top of the page. The click on DIAGNOSTICS to search by SYMPTOM, TROUBLE CODE, or read TECH TIPS on how to diagnose a problem

P0128 and temperature gauge dead – GM vehicles

Rick — Sat, 27 Mar 2010 00:07:38 +0000

If you get a P0128 diagnostic trouble code with your OBDII scan tool AND the temperature gauge is dead, head right for the thermostat When a thermostat goes bad on a GM vehicle, the PCM sets a P0128 trouble code and commands the cooling fans to run and disables the temperature gauge. Don’t waste time trying to fix the gauge. First, replace the thermostat. If the gauge still doesn’t work, then you can start diagnosing that problem after you’ve cleared the P0128 code.

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Engine surge at highway speed – Chevrolet Impala

Rick — Fri, 26 Mar 2010 23:54:47 +0000

Chevrolet Impala 1999-01 may experience a surge at highway speed. While this may be an air fuel related problem, it can also be caused by a slipping torque converter clutch. This happens when the torque converter clutch (TCC) is not fully applied. GM refers to this as a slip/stick condition. The TCC is applied with fluid pressure from a solenoid valve in the transmission valve body. The solenoid is pulsed by the PCM. In this particular model, Chevrolet has experienced some electronics failures where the pulsing is not correct. The result is a slipping TCC that can burn the transmission fluid and destroy the torque converter.

If you experience a surge at highway speeds above 40MPH, first check the transmission fluid to make sure the level is ok. Then check the fluid color. If it is dark brown and smells burned, you may have to pull the transmission and have it rebuild. But that’s not the full repair. You must also replace the PCM with an updated unit to prevent this from happening again. Chevrolet fixed the problem in the 2002 model year.

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Key won’t come out of ignition switch – GM vehicles

Rick — Fri, 26 Mar 2010 23:44:23 +0000

Believe it or not, this is related to a rash of bad ignition switches in GM vehicles. When the switch fails in the open position, it doesn’t provide battery power to the Brake Transmission Shift Interlock (BTSI) fuse. The BTSI system consists of the brake pedal switch and a solenoid on the shifting mechanism. The BTSI prevents you from shifting into and out of park unless your foot is pressing on the brake pedal. Unfortunately, when the ignition switch fails, the BTSI system also prevents you from completely shifting into park and removing the key.

To confirm that this is the cause of the problem, check for battery voltage at the BTSI fuse in the fuse box with the ignition turned OFF. If you don’t get voltage at the fuse, move to the ignition switch. Check for battery voltage at the B+ terminal. It should read within 1 volt of battery voltage. If not, replace the ignition switch

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No instrument panel, HVAC controls dead, blower motor dead, flashers dead, GM vehicles

Rick — Sun, 21 Mar 2010 07:36:08 +0000

Bad ground TSB for GM vehicles

GM has issued a TSB #04-08-45-010 covering 2004-05 Buick Rainier, 2002-05 Chevrolet Trailblazer, 2002-05 GMC Envoy, and 2002-03 Oldsmobile Bravada.

The bad ground connection can cause the instrument panel lights to be inoperative, HVAC controls inoperative, blower motor inoperative, radio inoperative, flashers inoperative, and transfer case controls inoperative. The cause has been found to be a poor ground at a splice area G201 located on the right side of the front console area.

To fix the problem, you must remove the center floor console. Then remove the 4 screws that hold the instrument panel lower closeout carpet panel to the instrument panel. Next, remove the panel.

Remove the splice pack bolt. If the bolt is corroded, clean it with a wire brush. Remove any carpet that was trapped during assembly. Clean the ground surface with emery cloth. Reassemble the panel and console.

Alldatadiy.com

eautorepair.net

Both Alldata and Eautorepair offer professional grade shop manuals at a price you can afford. Check them out!.

Hover your mouse over the REPAIR ARTICLES tab at the top of the page. The click on DIAGNOSTICS to search by SYMPTOM, TROUBLE CODE, or read TECH TIPS on how to diagnose a problem

Click on MAKE an MODEL to see all the articles I've written for your vehicle
Click on REPAIR TOPICS to read individual articles written for specific automotive systems

If you've had your car scanned and know the trouble code go to TROUBLE CODES

Here are some quick links to speed up your research

Click on the link below for speedy navigation:

ABS issues, how to bleed ABS brakes

Airbag issues or SRS light on

Alternator issues or how to test

Belt diagram or serpentine belt issues

Blower motor

Blower motor resistor

Brakes, brake issues, what kind of brake parts to buy, ABS issues

Car Alarms or Antitheft systems

Cooling system, Water pump, What type of coolant to use

Engine flush

Firing order, cylinder layout, finding #1 cylinder

MAF or MAP sensor

Oxygen sensors, How they work, How to change, How to test

PassLock or Passkey

Thermostat issues

Transmission flush

Serpentine belt diagrams

Window issues, power window motor, replace window regulator, glass adhesive

Oil Life Light Reset Procedure on Buick Rendezvous

Rick — Tue, 16 Feb 2010 04:37:07 +0000

The higher end Rendezvous vehicles have a Driver Information Center (DIC) that allows you to reset the oil life system. But if your vehicle doesn’t have that and you change the oil and find that the light doesn’t go out, you’ll have to do a manual reset.

Here’s how to do it: Turn the key to ON but don’t start the engine. Press and release the accelerator pedal slowly three times. You must complete this within three seconds. Then turn the key to the OFF position. If the Change Engine Oil light comes back on, repeat the procedure until it goes out and stays out.

Alldatadiy.com

eautorepair.net

Both Alldata and Eautorepair offer professional grade shop manuals at a price you can afford. Check them out!.

Hover your mouse over the REPAIR ARTICLES tab at the top of the page. The click on DIAGNOSTICS to search by SYMPTOM, TROUBLE CODE, or read TECH TIPS on how to diagnose a problem

Click on MAKE an MODEL to see all the articles I've written for your vehicle
Click on REPAIR TOPICS to read individual articles written for specific automotive systems

If you've had your car scanned and know the trouble code go to TROUBLE CODES

Here are some quick links to speed up your research

Click on the link below for speedy navigation:

ABS issues, how to bleed ABS brakes

Airbag issues or SRS light on

Alternator issues or how to test

Belt diagram or serpentine belt issues

Blower motor

Blower motor resistor

Brakes, brake issues, what kind of brake parts to buy, ABS issues

Car Alarms or Antitheft systems

Cooling system, Water pump, What type of coolant to use

Engine flush

Firing order, cylinder layout, finding #1 cylinder

MAF or MAP sensor

Oxygen sensors, How they work, How to change, How to test

PassLock or Passkey

Thermostat issues

Transmission flush

Serpentine belt diagrams

Window issues, power window motor, replace window regulator, glass adhesive

P0480 Cooling fan Chevrolet Cobalt 2.2L

Rick — Tue, 16 Feb 2010 04:28:33 +0000

This vehicle has a 2-speed cooling fan. If you run into the P0480 code and find that the fan will only run on the highest speed, start by checking for a blown cooling fan fuse #1 in the underhood fuse block. If that’s ok, swap cooling fan relay #1 with the high speed cooling fan relay #2. Both relays have the same part number.

Rest the PCM to clear the trouble code and drive the vehicle. If the low speed relay is bad, the swap will result in a new code, P0481. That will confirm that the relay is bad. Replace the low speed relay.

However, if the P0480 returns with the relays in their swapped positions, check the wiring harness for an open condition. Check the continuity of the dark green wire from the #1 cooling fan relay to the PCM, pin #47

Alldatadiy.com

eautorepair.net

Both Alldata and Eautorepair offer professional grade shop manuals at a price you can afford. Check them out!.

Hover your mouse over the REPAIR ARTICLES tab at the top of the page. The click on DIAGNOSTICS to search by SYMPTOM, TROUBLE CODE, or read TECH TIPS on how to diagnose a problem

Click on MAKE an MODEL to see all the articles I've written for your vehicle
Click on REPAIR TOPICS to read individual articles written for specific automotive systems

If you've had your car scanned and know the trouble code go to TROUBLE CODES

Here are some quick links to speed up your research

Click on the link below for speedy navigation:

ABS issues, how to bleed ABS brakes

Airbag issues or SRS light on

Alternator issues or how to test

Belt diagram or serpentine belt issues

Blower motor

Blower motor resistor

Brakes, brake issues, what kind of brake parts to buy, ABS issues

Car Alarms or Antitheft systems

Cooling system, Water pump, What type of coolant to use

Engine flush

Firing order, cylinder layout, finding #1 cylinder

MAF or MAP sensor

Oxygen sensors, How they work, How to change, How to test

PassLock or Passkey

Thermostat issues

Transmission flush

Serpentine belt diagrams

Window issues, power window motor, replace window regulator, glass adhesive

Pontiac Vibe part of the Toyota Accelerator Pedal Recall

Rick — Fri, 22 Jan 2010 22:46:43 +0000

Some 2009-2010 Pontiac Vibes may have the same accelerator pedal problem as the Camry, Highlander, Matrix, Tundra, and Sequoia. That's because the Vibe is built by the New United Motor Manufacturing Inc, a joint venture between GM and Toyota. The Vibes were built in the US at the Freemont, CA facility. But they were designed by Toyota and some have the same accelerator pedal.

See the full article here.

Chevrolet Cobalt Overheats

Rick — Tue, 19 Jan 2010 23:10:28 +0000

There’s quite a bit of overheating chatter about this vehicle on tech forums. If the cooling fans come on, try bypassing the heater core with a length of heater hose. If the problem goes away, you’ve got a plugged heater core. Also, check the hose from the engine to the overflow (surge) tank to make sure it’s not plugged.

If the cooling fan doesn’t come on, check the #1 (30A) fuse in the underhood fuse box. If that’s good, move on to check the relays. There are two relays even though there’s only one fan motor. Yeah, it’s a two speed fan. Both relays are the same part number, so swap them. If the fan works, replace the bad relay.

The power flows from the fuse, to the relays. The relay coils are controlled by the powertrain control module (PCM). Power to the relay coils also comes from the same fuse. The PCM just provides ground to the relay coils.

If the fan still doesn’t work, check continuity on the dark blue wire for fan relay #1 and the dark green wire for fan relay #2. Or, provide separate ground to either of those wires to see if the fan relay closes. Both wires go from the relay box to the powertrain control module. If there’s an open in either of those wires, the relay coil will never energize.

Alldatadiy.com

eautorepair.net

Both Alldata and Eautorepair offer professional grade shop manuals at a price you can afford. Check them out!.

Hover your mouse over the REPAIR ARTICLES tab at the top of the page. The click on DIAGNOSTICS to search by SYMPTOM, TROUBLE CODE, or read TECH TIPS on how to diagnose a problem

Click on MAKE an MODEL to see all the articles I've written for your vehicle
Click on REPAIR TOPICS to read individual articles written for specific automotive systems

If you've had your car scanned and know the trouble code go to TROUBLE CODES

Here are some quick links to speed up your research

Click on the link below for speedy navigation:

ABS issues, how to bleed ABS brakes

Airbag issues or SRS light on

Alternator issues or how to test

Belt diagram or serpentine belt issues

Blower motor

Blower motor resistor

Brakes, brake issues, what kind of brake parts to buy, ABS issues

Car Alarms or Antitheft systems

Cooling system, Water pump, What type of coolant to use