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Open Help Requests for GM
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2000 Buick LeSabre 3.8L temp guage
Car came in with over heating condition-after short diagnoses found that car was not over heating but temp guage was randomly jumping up to the hot side making the warning light chime-it would then go back to normal-cooling fan works fine-so far we have put a ...		 View
2004 Buick Rendezvous 3.6L No Start
Hello GM techs I am in over my head. As you can see I will be giving you scanner data from a Snappy, if you have seen this please email me. Using scanner data for 3X line will fluctuate an RPM signal. The 24X line stays steady at 336. I have unplugged the 24X... Trouble codes: p0336 (crank sensor fail location in block).		 View
2003 Cadillac Seville 4.6L radio system
This vehical has about a 2 amp drain. It is in the radio/amplifier system. I need help to condem the right part. It maintains this 2 amp drain all the time. After pulling both the 30 amp audio maxi fuse and the 15 amp radio mini fuse, then, the drain will drop...		 View
1995 Chevrolet Pickup 6.5L MIL Lamp on
I checked pc1 and pd1 ground and they are good. Are these the only grounds to this computer? The computer will not duty cycle the wastegate. the map is read 4.2v idle. Am i missing a ground to check? these are the only grounds my computer shows. Trouble codes: 78 (wastegate soleniod), 81 (2-3 shift solenoid circuit), 82 (1-2 shift solenoid circuit), 83 (tcc pwm solenoid circuit), 46 (mil circuit).		 View
1996 Chevrolet Monte Carlo 3.1L Poor Idle Quality, Stall
this thing chugs when its started after driven and sitting for about 20 min. It has not started a few times but when another shop put ignition mod on they didn't have the four wire connector installed completely.I unplugged the maf when its chugging and no cha...		 View
2000 Chevrolet Silverado 5.3L MIL Lamp on
installed new vent solenoid and lines and relocated filter per tsb. ran bay test with mastertech and po446 returns. opened purge with scanner and can feel vacuum at filler neck. open and closed vent valve with scanner and can hear clicking. i cannot read fuel ... Trouble codes: po446 (evap vent).		 View
2000 Chevrolet Monte Carlo 3.8L Stall
Good afternoon to all and thanks in advance for all your help.I have this 2000 Monte Carlo SS that we just sold last wednesday.Customer has complained of a intemitant stall.It has only staled 4-5 times with "no ryme or reason" as to when it stalls.Customer sta...		 View
2001 Chevrolet S10 Pickup 2.2L cooling
ac specialist please help,hello and thanks for all the help; 6-8 weeks ago installed reman compressor had no pressure with clutch engaged, flushed lines and cores replaced accumulator and oriface tube all ran great, customer returned past week no coolong syste...		 View
2003 Chevrolet Silverado 5.3L rear prop shaft speed sensor
truck brought in w/service 4 wd,found multiple codes u1000,u1255,c0300,c305,c0306,c0327,c0374,c0379,u1301.cleare d codes only code to return is c0300 rear prop shaft speed sensor circuit malfunction.have checked all wiring have ac signal out of sensor.please h...		 View
2004 Chevrolet Colorado 2.8L drum/shoes
Hey boys. I have several NAPA trucks with grabby rear brakes and noise at the end of the stop . All are colorado pick ups, all are 04-05 model year. One by one I have surfaced the rear drums per chevrolets tsb on this subject(however I found only 05-07 colorad...		 View
2006 Chevrolet Cab & Chassis Silverado 6.6L No Start
This truck was towed in, it stalled while driving down the highway, we had a low fuel rail pressure code and checked the fuel filter, it had alot of water in it, we replaced the filter and cranked it while watching the fuel rail pressure, we only got 378 psi, ...		 View
2007 Chevrolet Express 6.0L Lighting
I have this express that I need to put on a hitch and trailer wiring. The wiring diagrams show a series of "blunt cut" wires but where are they? And is there a better way to run wires than with one of those Hoppe kits that splice in behind both rear vehicle la...		 View
1995 GMC Pickup 4.3L hydraulic clutch
This truck came in with the master cylinder for the clutch broken at the end close to the line. I replaced the clutch master cyl and slave cyl with after market parts and both line seals were also replaced. Here is what happens I have bleed the system several ...		 View
1996 GMC Savana 5.7L IGN A fuse
Vehicle was towed in with a no crank situation and dash warning lights or gauges inoperative. Traced problem to blown 40amp IGN A fuse in underhood fuse box. Checked for shorts in circuit from fuse panel to ignition switch to starter. Tried replacing starter -...		 View
1999 GMC C7500 7.4L Excessive Emissions, Misfire
Although this truck has OBD II communications protocol, it isn't truely OBD II. For instance, it doesn't have a downstream O2S & there's no Mode 6 data. There are no DTCs. Many of the Tech II functions work fine, but there are no misfire functions. The Cylinde...		 View
2004 GMC Sierra 6.0L Stall, Reduced Power
Truck will start run fine and then intermittently go into reduced power mode and set P1516 and P2135. It has been happening since 2005 and customer has had this to numerous shops to try to get this resolved. See related repair history. Customer brought unit in... Trouble codes: P1516 (Throttle Actuator Control TAC Module Throttle Actuator Position Performance), P2135 (TPS 1 - 2 Correlation).		 View
1989 Oldsmobile Cutlass Calais 2.3L disk / pressure plate
Gentlemen I had this customer drive in with his clutch making a very loud rattling noise. Removed the tran and found some fingers on the pressure plate broken off at the end and causing the noise. Ordered a new clutch pac from NAPA ( only one shown for the ap...		 View
1998 Oldsmobile Cutlass 3.1L Cuts out
Car has good vacume good spark and good fuel pressure ..it stalls after half throttle no codes stored ..intermitant no comunication with scanner and can induce a codes . replace with known good parts ..map, mass air flow, Tps Iac .i'm out of ideas and customer...		 View
2002 Pontiac Aztek 3.4L 1-2 shift
had the transfer case gears blown up and reluctor ring came loose and broke causing shift problems and damaging the speed sensor. car was purchased by us after owner didn't want to spend money on repairs. . we replaced the transfer case with a good used one. r...		 View

Fixes & Summaries for GM
Fix/Summary Answers
1999 Buick Century 3.1L Poor Idle Quality
Tony from N. Carolina hit this one on the head! I scoped all of the crank and cam sensors again, all had a signal, but the 7x crank sensor signal was weak, almost no amplitude. Spec. for the sensor resistance was 900-1000 ohms, mine had 90. I scoped the same s... Trouble codes: P0449 (Evap system vent control circuit low).		 13
1991 Cadillac DeVille 4.9L security system
Thanks all, I've never had to do one like this before. I took the new key that came with the new lock cyl and the original key to the locksmith, had a new key made and every thing was fine. THANKS AGAIN]]]ED 		25
1997 Cadillac Eldorado 4.6L MIL Lamp on
Hey All,Thanks to All who replied.It was the intake gasket.We let the car sit overnight and smoked it.Did find the small amount of smoke near the bank 1 valve cover gasket coming from the intake gasket.Thanks again Alex [...]. Trouble codes: p0174 (lean bank 2).		 9
2002 Cadillac Seville 4.6L blower motor
I did find and fix this one. Turns out the ground for the module had a intermittent bad connection in the RH kick panel. There where all the grounds come together in one connector, the module ground wire was melting the connector, so I pulled on it and it come...		 6
1996 Chevrolet Cavalier 2.2L No Start, Stall
thanks to all who responded. there was some excellent and usefull advise, the ignition being one that stood out. we ended up replacing the PCM and the vehicle is starting without problem. customer has vehicle now and seems happy. we did make him aware of the p...		 14
2003 Chevrolet Cavalier 2.2L Dash vibration
Thank you for the replies a new front motor mount took care of the biggest part of the vibration but there was still a slight vibration with the ac on I did find one of the ac hoses barely making contact with the firewall after securing it away from the firewa...		 9
2004 Chevrolet Tahoe 5.3L signals
Thanks to all who sent a reply. We did find a problem but only time will tell if the real problem is fixed. Before we pulled the unit in the shop, in the parking lot the l/h signal turned on all signals but by the time we brought it into the bay, everything wa...		 11
2003 Oldsmobile Alero 3.4L Instrument Panel
Thank you all for taking the time to help. The fix was to remove an aftermarket radio wire that was spliced into the 1600 circuit behind the fuse box. Defective radio component was at times going to a dead short. Customer declined repairs to radio circuit. Af...		 3
2006 Pontiac Grand Prix 3.8L Hesitation, Cuts out, Stall, MIL Lamp on, reduced power
I had returned the vehicle to the customer until I was able to gather more useful info. Well, heavy rain this morning brought the car back - on the hook this time. It now had a new DTC stored: P0230 (fuel pump rly ckt). This made things considerably easier. C... Trouble codes: P1125 (APP sys fault), P2138 (APP sensor 1 - 2 correlation), U1000 (Comm error in EBTCM only).		 3
2001 Saturn L300 3.0L No Start
You don't see a rpm signal until it gets fuel pressure, and I knew it had a fuel pump problem, just that you think not 2 pumps.Only use oem pumps,and I think the problem was with the sending unit, it has the wiring harness for pump.I charged the battery and ke... Trouble codes: P0463 (fuel level snsr ckt signal), P0453 (evap pres sign high or open), P0123 (tp or app 1 ckt open or high), P0122 (tp or app sens 2 short or low), P0123 (tp or app 1 ckt open or high).		 4
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