Vehicle-- 1987 GMC v1500 4x4 350 tbi auto
Check engine light comes on but the truck will not give me any trouble codes only the number "12" trouble code which is "system pass". Is this truck not storing the codes anymore?Anyone else have this problem in where the check engine light comes on but the computer is not displaying any signs of trouble?Whats up??Thanks.
I am only using the simple jumper key(not a code scanner) to access the codes from the computer and just counting the amount of times the check engine light flashes.
2007-06-08 08:28:55 · 7 answers · asked by lift&shift 101 3 in Cars & Transportation ➔ Maintenance & Repairs
The truck runs good but i am very maticulous on my vehicles being in tip top shape hence the question of the check light.
2007-06-08 08:40:08 · update #1
There are some pretty helpful answers here.Sounds like i actually got some real mechanics to answer this time.I was finally able to retrieve the code #43.I replaced the esc module and now its fine.Thanks to eveyone and i will let this go up for a vote since everybody tried to help with some great answers.
2007-06-09 13:41:39 · update #2
Ok, if the light comes on, the ecm is signalling that there is a malfunction. Are you checking for codes with the engine running or do you shut it off and then turn the key back on? the reason I ask is because there are two types of codes, current and history. If a situation arises that causes the ecm to believe there is a malfuntion and is requesting the mil be illuminated, it should store a code in the ecm memory. But it could be a "soft" failure in that as soon as the key is cycled, the code is not stored any longer. Next time the light comes on, try stalling the engine by removing the power from the coil,or removing the coil wire if you feel brave, without turning the key off and check for a code. It seems like I have run into this some time before. Have you tried stopping by Autozone or the like to see if they can pull a code with their code reader? They don't have a diagnostic tool like a Tech 1 or tech 2 so they can't read the scan data just read the codes. They are basically doing the same thing like you are but their tool translates the code from the number to what system the code is referring to. If there is never a code stored, it sounds like it could be a faulty ecm. I'll ask a couple of guys I work with at Delphi Powertrain Systems. They've done a bunch of TBI swaps on off road vehicles and know the system inside and out.
2007-06-08 10:26:46 · answer #1 · answered by bbking48507 5 · 3⤊ 2⤋
Maybe there's nothing wrong?
(Check Engine Light)
There are many components that work together in the engine to maintain optimal engine performance and economy.
A service engine soon, or check engine light indicates that there is a sensor that is reading a condition that is "out of range".
Simply resetting the light does not solve the initial cause of the problem.
Replacing a number of parts trying to troubleshoot the problem in the hopes of getting the light to stay off is a tremendous waste of time and money.
The simplest, and most economical way to alleviate your issue, is to have an engine diagnostic done by a reputable shop to determine what caused the computer to signal you to begin with. Just reading the computer codes may not find the "cause".
That being said, if per-chance you feel the need to reset the light in the hopes that it was a "glitch" of some kind, you could disconnect the negative battery terminal for a couple of minutes to clear the check engine light.
Check you engine oil level.
2007-06-08 15:40:34 · answer #2 · answered by Mr. KnowItAll 7 · 3⤊ 2⤋
A problem with the air management system (air injection) will illuminate the check engine light without setting a code. It's called non EMC check engine light diagnostic. Find a good service manual to use for troubleshooting the air management system.
2007-06-08 23:17:10 · answer #3 · answered by Ron B 6 · 3⤊ 1⤋
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2014-04-09 21:59:35 · answer #4 · answered by ? 1 · 0⤊ 0⤋
It still has codes stored in the pcm. I believe there are 2 different ways to extract codes from this vehicle.....For the life of me, I can't remember how. You might have to hook it up to a scanner to obtain the other codes but I assure you it does have some stored in the pcm.
....I'm not at home right now so I can't tell you for sure but I will respond a little later with a better answer.
Sorry I couldn't help right now.
2007-06-08 15:38:11 · answer #5 · answered by creatingmars 3 · 3⤊ 2⤋
The GM dealer has an enhanced OBD-I scanner that can see what your problem may be. Otherwise, how is the truck running? Other than the check engine light, what is your complaint?
2007-06-08 15:35:26 · answer #6 · answered by bobweb 7 · 3⤊ 2⤋
sometimes the knock sensor will do this when your driving down the road it is picking up a engine knock. the light will stay on for a little while then go out , this happens when your putting some kind of load on the motor. good luck
2007-06-08 18:55:50 · answer #7 · answered by Anonymous · 3⤊ 2⤋