GM Automotive Technicians Technical Discussion and Fixes for Nov 16, 2005 - iATN (Members Only)

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Open Help Requests for GM

	Help Request	Answers
	2002 Buick Park Avenue 3.8L MIL Lamp on VIN: 1G4CW54K22 P0137 and P440 set vary rarely.( 3 times in 14,000m) Replacement fuel cap seems to stop P0440 from re-occuring. P0137 sets usually after 2-4 hours of highway speed running. It will set at 85mph or 62 mph randomly. Code set will clear out after 1 week of in tow... Trouble codes: P0137 (O2 sensor low bank 1 sensor 2), P0440 (Evap Emission Fault)	View
	1956 Chevrolet Pick-Up 396CID Differential Recently took truck apart to bare frame. Vehicle has a 396CID eng., 4 barrel AFB carb., want to put a high-end cam., with a 400 auto. trans., with a mild shift-kit. and a limited-slip diff. My question is what gear-ratio would give me the best performance with...	View
	1988 Chevrolet K1500 Cheyenne 4.3L Hesitation VIN: 1GCDK14ZOJ this is my truck. i've had this problem for a few years now.when truck is cold and you try to take off truck stumbles doesn't do anything, i have to push in clutch rev engine extra to get going then i have to feather the gas when shifting into 2nd 3rd. if i'm ...	View
	1996 Chevrolet Caprice Classic 5.7L No Start VIN: 1G1BL52P6T veh came in with complaint of no start; found dash light on "pass key fault"; diagnosed and replaced fault ignition switch and keys(standard broken wires at cylinder) went to restart veh and could not faound good spark, injection pulse good; veh had no fuel pr...	View
	1998 Chevrolet S10 LS 4.3L vacuum actuators VIN: 1GCCT19W0W We could clearly hear the switch leaking vacuum and none of the changing modes would happen. After panel replacement, still no change. After closer inspection we found all vacuum acuators have an oily substance in them, one actuator has the diaphram coming out...	View
	1998 Chevrolet C1500 Cheyenne 5.7L No Start VIN: 2GCEC19R0W Customer says vehicle started ok, and when shut off to go into store, would not restart. Engine starts and dies, and security light stays on. When you turn the key on, security light blinks 4 times, then glows steady. Have tried to relearn more times than I ca... Trouble codes: 1631 (Theft system password incorrect)	View
	2000 Chevrolet Silverado 1500 4.3L fuel gauge VIN: 1GCE19W4YZ Hello all you GM guru's, I need help with this one. The fuel gauge does not work, the temp gauge is inop, the message center flashes a battery icon with a low fuel message. This is what I have found. My scanner, Modis and Mentor, reading the pcm sees 14.2 vol...	View
	2001 Chevrolet Impala 3.4L MIL Lamp on, fALSE CODE??? I'm getting too old and/or too dumb for this line of work. I have an'01 Impala 3.4 that sets P0401 as soon as it gets a couple of blocks away; didn't think it would even run test that soon. Are there known reflash issues with these, or hidden TSB's, or am I j... Trouble codes: P0401 (low EGR flow detected)	View
	2002 Chevrolet Malibu 3.1L Starting system VIN: 1G1ND52J82 This car has no start condition, it happens every week or two. The problem has not happen in the shop. It has no trouble codes. The customer says she leaves it set for 10 minutes and it starts right up. She has tryed a different key and it still will not start...	View
	2002 Chevrolet Silverado 1500 5.3L Misfire VIN: 2GCEK19T02 Customers complaint high idle when cold (within first 10 sec.)than drop to a low idle with mis-fires (from 20 sec. to 2 min.) after a cold start )45F with mt2500 hooked up all data is within spec. had to let sit for 5-6 hours and restarted looking at mis-fire ...	View
	2003 Chevrolet Silverado 2500 HD 6.6L speedo VIN: 1GCHK2319F The speedo reads incorrect, 40mph while setting still, etc. The incorrect speedo is intermittent, however the scan tool receives correct speed readings indicating the speed sensor is feeding correct info	View
	2003 Chevrolet Suburban 1500 LT 5.3L MIL Lamp on VIN: 1GNFK16Z63 vehicle is flex fuel. the only fuel pressure spec that i can find is for koeo. 55-60psi.fuel pressure when running is 44psi at rail. if pressure is taken at outlet of filter before alchol sensor pressure is 54psi. inlet and outlet of alchol sensor are differen... Trouble codes: P0171, P0174	View
	1995 GMC Safari 4.3L Poor Idle Quality, Surge, Stall VIN: 1GTDM19W5S This van has high mileage & this problem is becoming frustrating, only pid that is out of scale is IAC counts. Smoke tested for vacuum leaks, none found. Major tune up was also perfomed, fuel pressure reading is 58 psi at idle, idle will stabilize at times but...	View
	1996 Oldsmobile Achieva SC 3.1L anti theft system VIN: 1G3NL12M7T Hello fellow techs...got a good one here. Problem with the passlock system. This car DOES NOT use a chip on the key. Sets a code 1629...car will start if you leave the ign. on for ten minutes to reset the system but if you shut it off you have to do the same t...	View
	1993 Pontiac Grand Am SE 2.3L No Start VIN: 1G2NE5435P Hello and thanks for your help. This car stalled in the street in front of the shop. When the engine cranks it bucks and jerks. It has spark to all the plugs. It has fuel delivery to the motor and injector pulse. There are no computer codes. The starter kicks ...	View
	1999 Pontiac Bonneville SE 3.8L Hesitation, Cuts out VIN: 1G2HX52K7X Ok this is a tough one. This car belongs to one of my co workers. We have been trying to figure this thing out for 6 months or so. What happens is that when you slow to make a left hand turn and then slowly accelerate the car falls flat on its face. You can le...	View
	2004 Pontiac Grand Prix GT2 3.8L power steering pump whine VIN: 2G2WS542X4 we have replaced the pump with a new gm unit and also flushed the system with gm power steering fluid. this did not seem to help at all. we also vaccumed down the entire system as to alldata installation instructions. the pump was replaced due to a noise probl...	View

Fixes & Summaries for GM

	Fix/Summary	Answers
	1995 Buick Park Avenue 3.8L No Start, Cuts out, MIL Lamp on VIN: 1G4CW52K3S Hi Guys! Sorry it took so long to get back top you. I've been in Florida on other business related issues. The problem with this monster was the PCM. We changed the pcm and the prom and the customer told me now the transmission shifts like brand new, the car r...	33
	1997 Cadillac Seville SLS 4.6L speedo, tach, prndl illumination, temp guage, tcs VIN: 1G6KS52YCV Hi Folks, I finally fixed this cadi thanks to some good advise from you guys. In my update on this one I mentioned how I checked the power stud under the hood (this was good) and I disconnected the trunk pulldown motor for possible interference with ground (th...	5
	2002 Cadillac Escalade 6.0L Steering Stability System VIN: 1GYEK63N92 Thank you, Terry, Dennis and Ken. You are right on. The steering position sensor cause an intermmittent problem. I removed the old sensor, inspecting-notice the outside and inside rings are loose. I have to wait a week to see if customer going to call me back....	4
	1990 Chevrolet R2500 Suburban Scottsdale 5.7L Oil Gauge VIN: 1GNGU26K9L Customer has not yet brought back to finsh repairs. I recieved lots of helpful imformation. I am going to pull cluster when he bring back an check restior on back of gauge. I will post again when all is well. Thanks	12
	1995 Chevrolet C1500 Suburban 5.7L 2-4 shift band VIN: 1GNEC16K3S Thanks for the replies. I had a lot of replies that said it sounded like a low pressure problem, but the only time I had low pressure was on the 2-3 shift. Others said to check the servo pin length and possibly shim it out, but the pin length was correct. One ...	13
	1998 Chevrolet Astro 4.3L No Start VIN: 1GCDM19W5X Exhausted all options, customer has a good used engine, opted to install, will update when it is in and running. Trouble codes: P0337 (Crank Sensor Circuit Low Frequency).	20
	1999 Chevrolet Blazer 4.3L MIL Lamp on, P0420 VIN: 1GNDT13W0X Well, a new oe cat fixed it, but I didn't get to do the fix myself. I guess my estimate was a bit more than she wanted to pay. She found someone to give it to her at cost. As it turned out, the bank 2 O2 heater did produce a code and that sensor was also repla... Trouble codes: P0420 (Catalyst System Efficiency Below Threshold Bank 1).	23
	2000 Chevrolet Astro 4.3L Headlights VIN: 1GCDM19W3Y Thanks to Ian, Scott and Gordon for their info. The customer brought the vehicle back today for further testing. We did check dimmer, high-beam switch & ignition switch - all OK. Having more time now we traced the related wiring harnesses wire by wire. We foun...	3
	2001 Chevrolet S10 2.2L engine VIN: 1GCCS14592 we removed torque converter bolts, vibration is still there, some suggested harmonice balancer, the balancer is solid and bolted ont a hub. most evetyone suggested unbolting the converter to confirm engine or converter.no onelse has worked on this one before.t...	12
	2000 GMC Savana 3500 7.4L Antitheft VIN: 1GTHG35JY1 After performing TSB for terminal connection, problem still returned..Found an intermittant voltage fluctuation to passlock module ignition feed wire..Would drop to 2.5 volts momentarily..The fix was to replace the ignition switch itself.(electrical portion)..... Trouble codes: B2960.	3
	2002 GMC Sierra 1500 SL 5.3L coolant VIN: 2GTEK19T02 Reid...you da man. Your efforts in finding the archive post aided the proper diagnosis immensely. We pulled both valve covers and found the left side only to have a large amount of coolant condensed on its underside surface. We then thoroughly cleaned all head...	17
	1992 Pontiac Grand Prix LE 3.1L Excessive Emissions, Poor Idle Quality, Hesitation, Misfire, Poor Fuel Economy VIN: 1G2WH54T7N I want to say thanks to all who replied. I was right when I said a vacuum leak at the lower intake gaskets, I just wanted someone else to say I was right. Anyhow resealed the lower manifold and all is well the miss is gone and the car runs like a champ. Thanks... Trouble codes: 35 (iac circuit malfunction).	21
	1995 Saturn SL2 1.9L Poor Idle Quality VIN: 1G8ZK5274S Sorry so long getting the close, but having to work around customer schedule of repair - found the on of the cam timing was off one notch - after finding the problem the customer remembered that the timing had been replaced and started after that several month...	8

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