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International Automotive Technicians Network
Prev Professional Automotive Repair Technical Discussions for February 7, 2005
International Automotive Technicians' Network (iATN) - Members Only
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Open Help Requests for GM
Help Request Answers
1969 Cadillac deville 4.6L Cooling Systems VIN: 1GCEL12Y4T
customer was told previously that the head gaskets were leaking(failed hydrocarbon test)so he added stop leak and drove for about two months. then the vehicle started over heating all of the time.we performed a hydrocarbon test and it passed. we found rad fan ...
1993 Chevrolet S10 4.3L Poor Idle Quality, Cuts out, Stall, MIL Lamp on VIN: 1GCCS19Z8P
Hello Fellow Techs, I have a 2wd s-10 that we installed a clutch and repaired cap rotor and wires also put a catalytic converter on,( plugged solid). test drove kept stalling out running rough but not 100% of the time. tap tested vcm thought a possible problem... Trouble codes: 55 (replace ecm)
1993 Chevrolet Astro 4.3L abs VIN: 1GHR34AZBZ
I have bleed the system many times her is how i did it i opened the internal bleed screws and then held in the reset switches on the bottom and then presure bleeed the system but still no pedal. If you look at the reset swiches on the bottom of the unit one sw...
1997 Chevrolet Venture 3.4L Cuts out VIN: 1GNDU06E1V
Thanks in advance for any help on this Venture van in for a missfire in passing gear. Well its more like a govener.Cuts out at around 4500 rpm.s in all forward gears(havent tryed reverse).Fuel preesure fine at 45psi. I've changed fuel filter,checked ignition,a...
1999 Chevrolet Cavalier 2.2L engine VIN: 1G1JC124XX
i have this 99 cav. that does not want to produce any heat. it came in with a complaint of driving down the highway the heat is not hot. test drove & coolant temp got down to 120 deg. put in a oe t-stat & drove again. same thing. pulled off lower hose & no coo...
1999 Chevrolet Silverado 1500 5.3L bucks VIN: 2GCEK19T3X
This truck under accel in drive will set U1041, turn on abs light and brake light, start to buck and lose data stream to the mastertech. You can create all this in the shop except the bucking while power breaking it in drive but not ever in reverse. In fact pu... Trouble codes: U1041 (Loss of EBCM comm.)
2000 Chevrolet Silverado 1500 5.3L coolant in the oil VIN: 1GCEK19T8Y
Hi to all and thanks ahead of time. We have a very clean one owner 2000 Chevy 1500 silverado pickup. All the sudden it started using coolant. The customer added coolant a couple of times . We drained the engine oil and found a lot of coolant in the oil. We ...
2000 Chevrolet Express 2500 5.7L Trans/ Engine VIN: 1GCGG25R7Y
Hi IATN members, Have tried to figure this van out but have had no luck. This van stalls when put into gear D or R and light power brake. Have had update for this condition from dealer TSB. Sent to trans shop for Tcc solenoid out of specs,drove a week. Va...
2001 Chevrolet Silverado 1500 4.3L No Start VIN: 2GCEC19W21
Hey guys have a hair puller, this truck was towed in had very weak spark, replaced cap and rotor, spark came was now normal, but we have no ground signal from computer to ijectors. fuel pressure is good. Of corse mitchell says replace computer, we did 2 differ...
2001 Chevrolet Impala LS 3.8L p0420 VIN: 2G1WH55K81
Have run car on Modis and shows OK. Fuel at speed looks good. Map and maf in range. LT fuel trim show -6 to -2 as you drive down the road log flat strech shows +2 to -3. Temp OK timing and all els look in spec. What have I missed? Trouble codes: P0420 (Cat Efficiency low bank one)
2002 GMC Sierra 1500 5.3L Poor Idle Quality, Stall VIN: 2GTEK13T84
hi master techs! need help on this one! I also have posted 0n gm tech forum. hold gas pedal to maintain 800 rpm for 2 min let off and vehicle almost stalls 300 rpm ,has stalled on me once so far cust concern is it does this on highway when exiting or even in c...
1995 Pontiac Grand Am SE 2.3L No Start, WEAK INJECTOR PULSE VIN: 1G2NE15D3S
this is a stranjge one, injectors 1-4 on one circuit 2-3 on another-if #1 is plugged in lose pulse on #4 or vis versa same with #2 or #3 if all are unplugged get a strong injector pulse im definetly scratching my head on this one and injector scratch test does...
2001 Pontiac Sunfire SE 2.2L abs module VIN: 1G2JB12411
This cars traction lamp, red brake lamp are on all the time with a code c1275, ECM request traction off. Power and ground at the pcm and ebcm are good. Any help would be appretiated.

Fixes & Summaries for GM
Fix/Summary Answers
1989 Chevrolet C1500 Cheyenne 5.7L 700r4 Trans VIN: 1GCDC14K8K
The fix was a replacment transmission 3-4 clutch pack was gone. Not sure if anything I did was to blame I did replace detent cable and added an aux. cooler and new tranny works fine Thanks for everyones response . Hope I can recepticate some day
1991 Chevrolet Caprice 5.0L compass
Well thanks everyone for the helpful advise! I took the Caprice to a parking lot last night and pointed it north, pressed the calibration button, and it's working great! Not sure why the car's owner's manual didn't tell me anything about this thing, other than...
1995 Chevrolet Blazer 4.3L Transmission VIN: 1GNDT13W3S
Well - as it turns out the 3-2 shift solenoid was bad. The scan tool through us for a loop. I gues you cannot rely 100% on the tools information. Thanks for all the support. It did help.
1996 Chevrolet Monte Carlo LS 3.1L Poor Idle Quality, MIL Lamp on VIN: 2G1WW12M9T
Well after pulling my hair out double checking every thing with the help of John Thornton we determined that the MAF was causing the lean condition and that the PCM was causing the high idle problem. The PCM was sending a very stange noisy signal on the 5v ref... Trouble codes: P0171 (bank 1 lean).
1997 Chevrolet K2500 5.7L Steering VIN: 1GCGK24R8V
After I purchased a P.S. pressure gauge set, I got the vehicle back in. I rechecked EVO output & checked pressure. It was a little higher than spec (175 instead of 120), but on a 2000 psi gauge it didn't bother me much. Slight turning of the steering shaft rai...
2001 Chevrolet Tahoe 5.3L Misfire, MIL Lamp on VIN: 1GNEK13Z82
i think this is a fix the car would only misfire cold i switched plugs around//coils and wires//but it never felt like ign miss only at idle//the fuel pressure was never right at idle so i warrantied a pump and that gained 5lbs with new filter//but would still... Trouble codes: P0300.
2001 Chevrolet Silverado 1500 4.3L Unknown VIN: 1GCEC14W91
I want to personally thank all 21 replies I received. Most all of the replies feel this is a very common problem with GM trucks.I found out from the posts there is a special GM lube for the yoke.Also there is a TSB stating to replace the yoke with a new nickel...
2002 Chevrolet Trailblazer LS 4.2L Drivers side temp VIN: 1GNDT13SX2
I pulled the control head out of the dash to gain access to the wires. I patiently tested all the wiring with a labscope. I found I could read a voltage drop out spike on the left temp actuator feedback circuit twice in about an hour of testing it. I also foun...
2002 Chevrolet Express 3500 5.7L 2 way radio VIN: 1G3NRY4VWM
Well I need to tip my hat to Daryn from Washington. he suggested to ck the cap & rotor for corrission I ended up taking some time off and one of our other tech look at the truck and ck the cap and found it to be bad. I want to thank all of the tech that offere...
2002 Chevrolet Impala 3.4L Hesitation VIN: 2G1WF55E42
Hey Guys, I appreciate all of the responses to this problem. As a few suggested I pulled the O2 sensor and checked the back pressure. I also took it for a road test with the sensor out of the pipe.What a difference in performance. As a fairly new vehicle I was...
1993 GMC K3500 Sierra 5.7L carrier case
thanks for the replies. at this point the veh. is back together as was. most replies suggested excessive wheel spin at some point[must have been previous owner]to cause case and side gear wear. Since there is no immediate problem i will schedule when its convi...
1997 GMC Safari SLE 4.3L No Start VIN: 1GKDM19WGV
we used the other tests the members advised and came to the conclusion the probelm was the fuel pump. we replaced the pump and took the old pump apart for inspection. we found that the brushes were burnt and the pump was going to totally fail very soon. the va...
1994 Oldsmobile Cutlass Supreme S 3.1L automatic door locks VIN: 1G3WH55M6R
Another problem solved thanks to iatn. Most everybody said to read the owners manual, that it should have a procedure to disable the automatic door locks. They were correct, the owners manual said to remove a 20 amp fuse #8 in the lower fuse pannel below the g...
1995 Oldsmobile Aurora 4.0L Poor Idle Quality, MIL Lamp on VIN: 1G3GR62C1S
Terry from florida helped a bunch.I do not have information on this vehicle it belongs to a friend and I work in a euro shop.Disconnected the battery,shorted the cables together,reconnect,roadtest for about 30 miles.Idle was relearned,all is good.Thanks Andy Trouble codes: 85 (throttle body cleaning required).
1997 Saturn SL 1.9L MIL Lamp on VIN: 1G8ZFS286V
I updated and reset the pcm with a GM flash reprogramer. It fixed the egr calibration problem, but created another. It reset the crank senson calibration. Neither of my scanners could relearn the crank sensor. I have a SNAP-ON and a GENISYS. Mitchell had no us... Trouble codes: P1404 (egr pos. incorrect).
1997 Saturn SL2 1.9L defogger VIN: 1G8ZK5279V
thanks again to you saturn tech's,,6 replys,,,help a lot,,after seeing electrical lay out,,,the door chime was the fix... thanks again for the help...new one on the way...i did a little wire jumping here and there,,,it has to be it (door chime module) new one ...
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