GM Automotive Technicians Technical Discussion and Fixes for Apr 19, 2007

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	Help Request	Answers
	1996 Cadillac DeVille 4.6L MIL Lamp on VIN: Y7TU298849 Code p0340 IC cam signal no freq comes on istantly. Have Good cam signal going to ign control module. No signal coming out to pcm. Check all grounds & wires to ign module & pcm have tried known good cam sensor, ign module, & pcm. Suspect cam timing off, if is ... Trouble codes: P0340	View
	1997 Cadillac Seville STS 4.6L oil pressure VIN: 1G6KY5297V installed new engine reman from advance auto parts customer called 3 days later no oil pressure. car was checked with mechanicl gage and had 80lbs pressure cold eng and went down to 2lbs hot engine. new engine was installed and same problem. have torqued harmo...	View
	1997 Cadillac Seville SLS 4.6L instrument lights VIN: 1G6KS52Y5V this Cadi will not light up the instrument panel at night , all gages work properly , digital odometer works bright, the dimmer control will vary when checked at the cluster input. the same cluster work with the lights on another cadi. Is there anything else t...	View
	2001 Cadillac DeVille 4.6L oil usage VIN: 1G6KD54Y51 customer has complaints of using oil about every 2 weeks she has t add 2 quarts.have dye checked it and can not find any leaks.Is there anything that can be added to slow down the oil usage" the other problem is how to get the light off in the dash fore the ti...	View
	2005 Cadillac DeVille DHS 4.6L Tire Press Monit Sys VIN: 1G6KE54YX5 The customer has asked me if there is a way to reprogram the system so that he may run more than 38 psi in his tires. The new tires installed on car are rated at 44 psi max. When tis amount is put in, the system indicates that the tires have too much air pr...	View
	1994 Chevrolet K3500 7.4L Poor Idle Quality, Stall VIN: 1GBJK34N4R IT WILL START AND DIE. iT WILL RUN JUST FINE WITH PLENTY OF POWER W THE FUEL RETURN BLOCKED OFF. AS SOON AS YOU RELEASE THE RETURN IT WILL DIE. WILL A NEW FUEL PRES REG BRING THE FUEL PRESSURE UP TO0 WHAT SPEC IS OF 26-32 PSI. 93 AND PRIOR IS 10-15 AND 94 AND9...	View
	1999 Chevrolet Astro 4.3L trans this is a 4l60e trans. overhauled 300 miles ago, was working good untill driving at 45 mph and she said it reved up and would not pull. her brother looked at it and said it will pull if you put it in man 1st and up shift through all 4 gears if shifted manually...	View
	1999 Chevrolet Express 2500 5.7L abs module VIN: 1GCGG25R2X hello everyone, hopefully someone can shed some light on this one. came in about a month ago fr left brk pads were metal to metal. nreplaced calipers everthing was good to go. cust now complains of a hard pull to the left when braking. we rebled system no air....	View
	2002 Chevrolet Trailblazer LS 4.2L MIL Lamp on, power loss VIN: 1GNDT13S12 This vehicle is its third time in. The 1st time it had code p1271 accelerator position sensor correlation & a code for camshaft position sensor. We scope the camshaft position sensor and found a bad signal. Replaced camshaft position sensor and accelerator ped... Trouble codes: P1271	View
	2002 Chevrolet Cavalier 2.2L starter Hey good morning guys I recently did a head gasket job when I was done the car started turned it off then when I tried starting it again the car wouldnt crank. When I bypass the starter solenoid the car will start I was wondering if any body had any ideas why ...	View
	2002 Chevrolet Trailblazer LS 4.2L Poor Idle Quality, Hesitation, Misfire, MIL Lamp on VIN: 1GNDT13S22 Hello all. I have a good one for you GM techs out there. This 2002 Trailblazer came in for bogging down at idle and client feels engine miss. The misfire counter on the Modis counts up and then resets on cylinders 3 and 4. We replaced the spark plugs and boots... Trouble codes: P0105 (Manifold Absolute Pressure System Performance), P0130 (HO2S Circuit Bank 1 Sensor 1), P0304 (Misfire Cyl 4), P0300 (Random misfire)	View
	2003 Chevrolet Silverado 2500 HD 6.6L No Start VIN: 1CTHK29183 Ok first off... this is NOT the correct vin. we do not have a good #. this duramax is being dropped into a trans am drag car.. I was asked to help with the wiring issues..first off the ecm (used) and bcm (used) and tcm (used) all may be from different trucks. ...	View
	2004 Chevrolet Silverado 2500 HD 6.6L speedo VIN: 1GCHK23294 can hear bearing type noise int, & then speedo jumps, & brake lite will come on, will go out on own after several miles, will set code co 055, did see voltage bobble at speed sensor, replaced sensor & could not verify any more fluctuation., but still have trou...	View
	2005 Chevrolet Express 2500 5.3L Daytime Running Lights & Running Lights VIN: 1GCGG25V25 Vehicle came in with the daytime running lights inop. The front and rear running lights turn on when the DRLs are supposed to be on and are inop under all other conditions. We replaced the headlight switch with no change. Fuses are all good. Bulbs and wiring a...	View
	2004 GMC Sierra 1500 SLE 5.3L tcc VIN: 2GTEK19T94 Thanks in advance for your time, very bad torque converter shudder, replaced with GM converter, now there is no shudder but at 45 - 50 mph tcc will enable and duty cycle will fluctuate between 19 - 22 % , converter slip will be 60-80 rpm then will go to 0 then...	View
	2000 Oldsmobile Bravada 4.3L Mechanical VIN: 1GHDT13W6Y I have an Olds Bravada with AWD. The tranfercase seems to be locked in 4wd. No codes and have flushed the case per GM. It is the 136 case so it is the 1 speed active system. Looking at the wiring diagram in Alldata the control module can only command the motor...	View
	2001 Oldsmobile Intrigue GL 3.5L MIL Lamp on VIN: 1G3WS52H71 Car came in with 2 codes one for trans and the p0410 for secondary air injection system. Did trans and got rid of that code(adabtive shift stragity at limit). Now this other code is haunting me. Went through the entire dioag. check and all checked good. Air in... Trouble codes: P0410 (Secondary Air Injection System)	View
	2001 Oldsmobile Intrigue GL 3.5L MIL Lamp on VIN: 1G3WS52H91 came in with p0410 for secondary air injection & p0412 for soleniod fault. can not comand soleniod to ground to allow vacuum. trouble tree for p0410 indicates if code p0412 is stored diagnose first. replaced pcm and reprogramed as stated, still unable to pul... Trouble codes: P0412	View
	1997 Pontiac Grand Am SE 2.4L Rear Brakes VIN: 1G2NE52T5V This has been a problem for this customer for quite some time, but it is getting worse. Upon light braking at 2 to 3 mph the rear wheels will lockup, and activate the ABS system. At normal speeds and normal braking, they work pretty well, but in a moderately h...	View
	2001 Pontiac Grand Prix GT 3.8L MIL Lamp on VIN: 1G2WP12K61 the usual s.e.s.lite on ,scan using o.t.c.genisis. have code p1404a egr closed performance . replaced egr valve .clear codes road test , seslite comes back ,same code, lite only sets at idle or oncoast . data stream with key on eng.off says egr learned min. po... Trouble codes: P1404	View
	2002 Pontiac Montana 3.4L Engine VIN: 1GMDX03E92 Hi group, thanks in advance for any help. I don't have a lot of these screw ups, but now and then... I had this van in last week for the intake gasket, all went well, and the customer picked it up. It came back 2 days later on the hook, with no oil in it and k...	View
	2003 Pontiac Aztek 3.4L rear differental VIN: 3G7DB03E23 customer came in with noise in rear differental. took rear diff. apart and found bad carrier bearings and races. the only parts that I can get from gm is axle seals and pinion seals. I found after market bearings but there is 4 seals inside of diff. that I can...	View
	1994 Saturn SL 1.9L Excessive Emissions, Poor Idle Quality, Hesitation, Stall VIN: 287766BG38 hi, i am woriking on a 1994 saturn ls. engine run very rich and idle flutuating when hot. new idle air controle. map and tps is woring good. it has a lost of black smog. any one has any advice? thanks	View
	2001 Saturn L200 2.2L theft deterrent VIN: 1G8JU52F51 Hello- I have just replaced the trans in this car with a used trans. All connectors look ok,nothing unplugged etc.. However will not start. It will start for a couple seconds and then die. I thought it out of gas because gauge reads virtually nothing so put a ...	View
	2002 Saturn L200 2.2L Mechanical VIN: 1G8JU54F22 HELP SATURN TECHS, we are trying to install a new timing chain kit, bought new from local Saturn dealer, Problem is when we line every thing up, we pop the tensioner out against the guide, we then turn the motor over by hand going clockwise to make sure everyt...	View

Fixes & Summaries for GM

	Fix/Summary	Answers
	1996 Cadillac DeVille 4.6L No Start VIN: 1G6KD52Y6T Hello everyone, Thanks to all who helped...It turns out that the bottom end came apart and when we pulled the crank sensor, It had a chunk of metal attached to the magnet. Put a new one in and it had spark. Still cant start it because of lower end damage, But ...	8
	1997 Cadillac DeVille 4.6L idler pulley VIN: 1G6KD54Y0V Checked motor mounts and power steering and other pulley alignments with no problems found. Replaced helicoil insert and installed new idler pulley/bolt assembly and have had no more problems. The bolt was broken off below the flange surface, so I'm thinking t...	3
	1974 Chevrolet C20 Pickup 5.7L fuel gauge VIN: CCY244Z137 thank you brad for the schematic, and thank you all for the replies. it turns out the previous owner had repaired/replaced the wire before. they changed the wire color ( from tan to yellow) and did a good job of hiding their junction (which was broken). repair...	15
	1985 Chevrolet K10 Scottsdale 5.7L Pwr Windows VIN: 2GCEK14H7F Special thanks to Kevin [...]. Prinvale for the faxes. I was able to obtain the last (6) of these clips my local Chevy dealer and with the schematics available, fix this beast. I also found out it has a bad passenger pwr. window switch and finding th...	7
	1987 Chevrolet S10 Blazer Sport 2.8L basic brakes VIN: 1GNCT18RXH THanks all for the info. Still have not corrected the problem. Tried new rotors, installed an electric vacuum pump from an 06 chevy. Still not better. I am now going to put an 80 grit unidirectional finish on the rotors and see if that helps. Thanks, Paul	21
	1994 Chevrolet Caprice Classic LS 4.3L No Start, Cuts out VIN: 1G1BN52W4R I would like to thank all replies, especially kevin he was the one who pointed us in the right direction. After changing the distrib for the third time,i found out that the tech I had check wiring harness did not back probe, had disconnected the sensor harness... Trouble codes: P0016, P0036.	4
	1996 Chevrolet Blazer 4.3L serp. belt VIN: 1GNDT13WXT First off let me thank everyone who replied. All of you had excellant ideas and some of them had been tried. But all of you who had mentioned a tsb about belt noise ,from GM or had mentioned a power steering pulley on to far or not far enough all get the prize...	37
	1999 Chevrolet Venture 3.4L MIL Lamp on VIN: E7XD326778 you guys were right again. the sensors are on the same circuit and after i changed the cam sensor it was all good. i changed the ks because the customer just 'wanted ' it incase. thanks guys that same sensor thong threw me off i should have labed scoped it and... Trouble codes: 327 (341 -), 341.	4
	2001 Chevrolet S10 2.2L starter will not engage VIN: 1GCCS14591 thanks to all who replied, as many suggested i ran a new ground to the relay ground , i also replaced the down stream o2 sensor as i had a malfunction code. ground cable was cleaned at trans lug. test drove car many times and had no problems, customer called m...	10
	2002 Chevrolet Express 3500 6.5L Horns VIN: 1GDJG31F52 Well we recieved this van last week to install another set of horns. Upon installing, they blew right away (which almost made me loose my lunch). My co-worker informed me that an employee of the van company had tried to fix it himself. I wish him luck. Thanks ...	4
	2004 Chevrolet Silverado 2500 LS 6.0L No Start VIN: 1GCGK23U54 search wiring to ignition housing repaired ground to housing sensor. also repaired grounds to engine block.	11
	1998 GMC Savana 2500 5.0L abs module VIN: 1GJFG25M5W well this was a new one on us. we ended up finding that the spider gears in the rear end had worn 4 teeth off enough that when slowing down it would skip over a tooth causing the driveline to increase and decrease speed for a split second and cause abs to come...	5
	2002 GMC Sierra 2500 SL 6.0L Rear wheel speed sensor and speedometer VIN: 1GTGK29U72 Sorry about the delay on closing this request. Our customer decided to 'live with it' until a later date. Once he allows it to happen, I believe the fix will be an aftermarket programmer or ratio adapter. I confirmed that both front and rear ratios were 4.56 a...	9
	2002 GMC Sierra 2500 SL 6.0L Transfer case shift VIN: 1GTGK29U72 Sorry about taking this long to close this post. Our customer decided to wait on this and another problem for a later date. I had good suggestions regarding the shift motor and a possibility of it being related to the ABS problem. Thanks again.	4
	1997 Pontiac Grand Prix SE 3.8L Poor Idle Quality, Misfire, MIL Lamp on, LEAN VIN: 1G2WJ52K8V fixed! did another leak down test with another tester found the problem to be a valve seat or valve problem customer decided to go for a used engine instead of a valve job engine is in and runs like a top Trouble codes: P0300 (radom misfire).	11
	2001 Pontiac Aztek 3.4L cooling fans VIN: 3G7DAO3E41 Thanks for all the quick replies.I waited a couple of weeks to summarize this issue because i wanted to be sure the customer was ok with the guage problem. With all you guys to back me up I could tell her with full confidence that the fans were coming on at ex...	12
	2003 Saturn Vue 3.0L bcm VIN: 5GZCZ63B53 THANKS TO all who helped, i took it to the dealer and they reprogrammed it, now all working to specs...thanks again	5

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