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Prev Professional Automotive Repair Technical Discussions for February 1, 2010
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Open Help Requests for GM
Help Request Answers
1999 Buick LeSabre Limited 3.8L HVAC display VIN: 1G4H52K2XH
I have a Tech 2 and need to know how to change the HVAC display from Cel to Farenhiet. Changed Battery in car and now diplay reads celcius.
2002 Buick LeSabre Limited 3.8L abs light VIN: 1G4HP54K12
Hello all, this 2002 Buick LeSabre has the ABS, Traction Control, & Brake light on. System has codes C1214 & C1248 codes in memory. Powers and grounds at module check good. Unable to clear codes. Replaced ABS module (elect side) W/ Delco part 2 times. All ligh...
1991 Chevrolet Camaro RS 5.0L PCM, Cal pac, prom VIN: 1G1FP23E2M
The Camaro came into the shop with the idle running too high and no data from the ALDL connector. We corrected the wiring to the ALDL and when we read the data we had the MAT temperature reading all over with no rhyme or reason. We checked the wiring from the ...
1998 Chevrolet Blazer 4.3L Trans-Case VIN: 1GNDT13W2X
Vehicle was brought in with a does not go into 4 wheel drive complaint. Also customer complained the service 4 wheel drive light on dash is on. Performed inspection and was able to duplicate problem, we erased code and the service 4wd light on dash went off....
1998 Chevrolet Tahoe 5.7L Compressor VIN: 1GNEC13R5W
Whats occuring is the control head is shorting out and no longer sending the 12v sgnal to the PCM. The Lt. Green wire pin 10 conn3 is supposed to be a 12v signal through a high pressure cut-out and to the PCM that inturns grounds the relay to engage the compre...
2002 Chevrolet Tracker 2.0L Ignition coils VIN: 1G1ND52M1W
First of all thanks for any help and input you have, Second the vin supplied is for my own vehicle not the vehicle in question, Now what I have is a towed in tracker first time customer. Customer was driving down the road vehicle quit and will not restart, I h...
2004 Chevrolet Silverado 2500 HD 6.6L MIL Lamp on VIN: 1GCHK24154
The customer brought us the truck due to the MIL being on. We cleared the code and gave the truck back. The light stayed off for a couple of days but then came back on. The same codes are present as the first time. We have checked and cleaned all grounds. My n... Trouble codes: P0700 (Trans control system fault), U1800 (lost communication with FICM), U2104 (CAN bus reset counter overrun), U2106 (Lost communication w/trans control system)
2005 Chevrolet Silverado 1500 HD 6.0L Speedometer VIN: 1GCGC13U25
This customer complained of the speedometer reading too slow and lower than expected power when towing his 3000lb trailer. I used the TECH 2 to check the tire size calibration figuring that would affect trans shift points. The scanner showed no tire calibratio...
2006 Chevrolet Impala LT 3.5L engine oil low / add oil message VIN: 2G1WT55K06
Customer came in for LOF and complaint of "engine oil low / add oil" message on. Checked oil level (1/2 Qt low), changed oil, and found switch still open after refilling with oil and PID reading low oil "yes". Installed new GM switch. Switch now closes with ab...
2006 Chevrolet Monte Carlo SS 5.3L Poor Idle Quality, Misfire, Poor Fuel Economy, MIL Lamp on VIN: 2G1WL15C86
This is driving me crazy. After a short drive and usually if you accelerate a little harder than normal this starts missing real bad most of the miss fires are on #4 cylinder. The other cylinders have slight miss fires at times. After a short drive and I let i... Trouble codes: P0300 (miss fire detected), P0053 (b1s1 heater resistance range), P0134 (low o2 activity b1 sensor1)
1988 Oldsmobile Delta 88 Royale 3.8L Stall VIN: 1G3HN14C2J
Ok this car is stumping me need help! Vehicle dies when hot, doesnt stumble or have a hesistation. Had a code in system code 42 electronic spark timing (EST) problem. Ran a tap test on igntion module and car died maybe just a quincidence. Replaced ICM and veh... Trouble codes: 42 (Electronic spark timing EST problem)
1996 Oldsmobile 88 Royale 3.8L MIL Lamp on VIN: 1G3HN52K8T
been fighting this car off and on for about 2 monthes. car first came in with check engine light on. found p0440. after smoking system and working purge and vent valves numerous times found vent valve sticking and cracked hoses going to canister. replaced vent... Trouble codes: P0440 (evap system)
2005 Pontiac Montana 3.4L high idle VIN: 1GMDV03E45
Intermitantly this vehicle has high idle.Customer claims that they dont have to touch the gas to go the speed limit.We have never caught it happening.We have installed a TPS,cleaned throttle body,checked wiring at trans case for shorts and also TPS and IAC con...
2001 Saturn L200 2.2L dash light VIN: 1G8JU52F81
I checked charging system originally and found that the battery had a bad cell. Replaced battery and checked charging system. Alternator had an internal failure. Replaced alternator and vehicle is now charging at 14.6 volts. However the battery light on in the...

Fixes & Summaries for GM
Fix/Summary Answers
1985 Chevrolet S10 Blazer 2.5L Hesitation, Stall, backfire VIN: 1GCBS14E0F
first iwould like thanks everyone for the advise, i remove the cam as most of you told me, and i did not found anything wrong so i decided take apart the all engine and i found that the head was diferent , the original head had a heart form in the lower side, ...
1996 Chevrolet Tahoe 5.7L p1870 VIN: 3GNEK18R0T
bad valve in the valve body a replacement valve and the truck was back on it feet again , just a small note *** if you put a high output tc then you need to put a high out put valve body thanks to all that help and i hope i can help you guys one day
1999 Chevrolet Express 1500 4.3L Hesitation, Cuts out, Misfire, MIL Lamp on
Thanks to all for the helpful advice. This van had multiple problems and issues,after tackling one problem at a time we finally got to van to run with NO misses underload. Even though my snap on modis showed crank and cam funtioning properly, we chanced it and... Trouble codes: P0300.
2000 Chevrolet Astro 4.3L Cuts out, MIL Lamp on VIN: 1GMDM19W3Y
First of all i would like to say thank you to everyone who took the time to reply. To those of you that suggested changing out the distributor you were right on the money. We changed out the distributor and took it out for a test drive and the van did not miss... Trouble codes: P0300.
2003 Chevrolet Avalanche 1500 5.3L Poor Idle Quality, engine noise VIN: 3GNEK13T43
Thank you to all of the techs that sent in their recommendations. Of the 14 replies that I received, the ones that pointed to a restricted or plugged catalytic converter issue were correct. The left side cat. was plugged and causing all of the carbon and oil...
2004 Chevrolet Trailblazer LS 4.2L Battery Light VIN: 1GNDT135X4
Hey guys and thanks for the info. I do not consider this a 'fix' as there is no real proof & data to go with it. But the customer called and said the light went off the next morning and never came back on. The only thing we can think of is that it was a moistu...
1999 GMC Sonoma SLS 2.2L No Start VIN: 1GTC1940X8
well like to say i fixed this one but when truck in shop no isuses so we put launch crecorder on it and it did pick up any thing wrong with the truck we are starting to think we may have air flow sensor isuses well if we do figure it out we will let you know ...
2000 GMC 3500HD 7.4L Misfire VIN: 1GDKC34J5Y
I would like to start off by saying thank you to all who responded, I greatly appreciate it. Just as I suspected, the problem was injectors. Had to replace 3 on the left bank and the vehicle is running fine now. Trouble codes: P0131 (p0134-), P0134 (p0135-), P0135 (p0154-), P0154 (p0155-), P0155 (p0171-), P0171 (testing and results).
2003 GMC Envoy XL SLT 5.3L Engine VIN: 1GKET16P93
My bad, I thought I closed this already. Anyway, I finally came to the point that I didn't care how much it looked like a headgasket, I can not believe that a headgasket can be intermittent. After much thought and going over in my head the 2 moments I saw th...
1996 Oldsmobile Cutlass Ciera 3.1L No Start VIN: 1G3A153M0T
customer opted to try a used pcm. after 3 tries from the local wrecker we finally got a pcm that worked in this unit. all the others looked right but came with their own symptoms. the owner has the vehicle now and is going to drive it for a week and let us kno...
2003 Pontiac Grand Prix GT 3.8L runaway idle VIN: 1G2WP52K73
ireplaced plenum gasket and these other parts trying to solve the idle problem .i have also eliminated throttle body movement as well as throttle cable and cruise . ive done wiggle test connector cleaning and reconnecting .its as if the computer is commanding ...
2002 Saturn L300 3.0L heater VIN: 1G8JW54R52
used car lot car someone let the center vent grill fall down in the heater box so the blend door would not move thanks john
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