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Username Post: Service engine soon light on 1992 suburban        (Topic#180170)
Stefan E. 
Member
Posts: 113

Age: 37
Loc: Fauske, Norway
Reg: 11-16-03
01-21-08 08:09 AM - Post#1347654    

Hi guys

Can anyone tell me how I can manually retrieve the engine DTC on my 1992 Suburban K2500 with 5,7TBI?

Sometimes the "service engine soon" light comes on, and earlier this only happened on longer trips, about an hour drive or so, but lately the light comes on sooner. Just driving to work ten minutes away may trigger the light.

I don't suspect it is anything serious, I don't notice any change in how it runs. And if I stop the engine and start again, the light is gone for a while.

I did find the fault codes for the ABS module, with a wire between terminal A and H on the connector. Is it the same thing for engine codes?

Thanks

Stefan

BTW: Maybe I should mention that the truck is converted to run on LPG. But the light also does it's thing when only driving with petrol.

Edited by Norwegian dude on 01-21-08 08:10 AM. Reason for edit: No reason given.

 
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Chris O. 
Member
Posts: 145
Chris O.
Age: 41
Loc: Cedar Springs, Michigan
Reg: 10-01-05
01-21-08 08:28 AM - Post#1347670    
    In response to Stefan E.

Go here CFM TECH This should net you some good info.

Chris
'99 Z71 2 Door Tahoe


 
Chevytech 
Subject Matter Expert - Senior Member
Posts: 3092

Loc: Twin Cities, Minnesota, U...
Reg: 04-25-04
01-21-08 09:30 AM - Post#1347720    
    In response to Stefan E.

Here are some web sites with the basics on retrieving codes without a scan tool or code reader.

Poor drawing of ALDL but ok instruction + codes
http://www.cfm-tech.com/gm_tbi_trouble_codes.htm

OBDI terminal identification
http://robertpowersmotors ports.freeservers.com/ima...

OBDI illustration and instructions
http://www.troublecodes.net/GM/

1985 – 1990 trouble codes instructions
http://www.iroczone.com/specs/TroubleCodes.htm

Let us know what code or codes you find.

For those of you that are wondering why you are not getting replies to your thread:

Did you give the model, year, engine, fuel system type, and transmission information?

If the it has been altered from stock let us know about that too.


 
Stefan E. 
Member
Posts: 113

Age: 37
Loc: Fauske, Norway
Reg: 11-16-03
01-21-08 09:53 AM - Post#1347747    
    In response to Chris O.

Thanks a lot! It was easy! Turned out I had a code #32, which should be EGR system.

Do you disconnect the whole EGR system, or do you fix it? Any common problems and quick fixes?

Stefan


Stefan E.
1992 Suburban K2500 5,7 TBI


 
someotherguy 
Moderator
Posts: 25969
someotherguy
Age: 44
Loc: Texas
Reg: 08-01-03
01-21-08 09:56 AM - Post#1347749    
    In response to Stefan E.

From our FAQ - http://www.chevytalk.org/fusionbb/showtopic.php?ti... a thread discussing EGR diagnosis; gets into the meat of it about 3/4 down the first of two pages.

If your EGR valve is original from 1992 it's probably the valve itself that has gone bad, but before spending the bucks to replace it, you should go through the diagnosis first. The only way to be sure you get the correct valve is to get one from the dealer, and here in the States they cost about $75 - surely to cost you more. The generic parts house ones are often more trouble than the money you save, resulting in drivability problems.

Richard
94 C2500LD / 97 Suburban LS1 / 06 300C SRT8
Check out my truck shop projects


 
Chevytech 
Subject Matter Expert - Senior Member
Posts: 3092

Loc: Twin Cities, Minnesota, U...
Reg: 04-25-04
01-21-08 10:12 AM - Post#1347758    
    In response to Stefan E.

I was putting together this reply and then saw Richard posted a link to another post. Look at the other post and read this reply and let me know if you have any questions.
_________________________ _________________________ __


Specific criteria / driving conditions must be met for a code 32 to get set.

The computer monitors the EGR effectiveness by momentarily de-energizing the EGR solenoid which shuts off the vacuum to the EGR valve. With the EGR closed, the fuel integrator counts must fall within calibrated window that is greater then during normal EGR operation. (The Mixture called for must change an expected amount). After failing the test twice a code 32 will be set.


This code usually gets set because the EGR does not work.

The first thing to test:
Try to manually open the EGR by lifting the diaphragm by hand at idle and see if the engine kills. Be careful not to burn your figures or get them caught. If the passages are plugged there will be no difference in the idle when you open the EGR valve.

Also check the vacuum hose to the EGR solenoid and make sure vacuum is getting to the solenoid.
For those of you that are wondering why you are not getting replies to your thread:

Did you give the model, year, engine, fuel system type, and transmission information?

If the it has been altered from stock let us know about that too.


 
Stefan E. 
Member
Posts: 113

Age: 37
Loc: Fauske, Norway
Reg: 11-16-03
01-24-08 11:41 AM - Post#1350168    
    In response to Chevytech

I havent had the time yet to check these things. But I think maybe the valve's not all gone bad, but just not working 100% like it should.

The light hasn't come on now for a few days, and the engine is running fine. Like I said, about a year ago the light never came on. It startet comin on sometimes on longer trips, and have now gotten worse. It comes on sooner and sooner.

Sometimes it idles a bit rough, and then other times it runs really smooth. I suppose that if there was anything positive wrong, like a broken vacum line or something, things would be a bit more consistant.

But someday I'll have to go out and take a look at it...

Thanks guys!




Stefan E.
1992 Suburban K2500 5,7 TBI


 
Chevytech 
Subject Matter Expert - Senior Member
Posts: 3092

Loc: Twin Cities, Minnesota, U...
Reg: 04-25-04
01-24-08 12:45 PM - Post#1350206    
    In response to Stefan E.

  • Norwegian dude Said:
I havent had the time yet to check these things. But I think maybe the valve's not all gone bad, but just not working 100% like it should.

The light hasn't come on now for a few days, and the engine is running fine. Like I said, about a year ago the light never came on. It startet comin on sometimes on longer trips, and have now gotten worse. It comes on sooner and sooner.

Sometimes it idles a bit rough, and then other times it runs really smooth. I suppose that if there was anything positive wrong, like a broken vacum line or something, things would be a bit more consistant.

But someday I'll have to go out and take a look at it...

Thanks guys!



  • Chevytech Said:

Specific criteria / driving conditions must be met for a code 32 to get set.



Depending how you drive your vehicle the test criteria may not hit often. I have seen a vehicle with the EGR passages totally blocked with carbon, and the vehicle owner said the light only comes on about once a week.

(Here is the info for a 1993 C/K TBI 5.0, 5.7 and 4.3L (s/t))
The actual test that sets the code 32 is done when:
-Throttle position is between 10% and 25% angle
-Steady throttle with no more then 2% change in throttle
-Above 32 MPH closed loop operation
-Max short term fuel trim less then 6 counts for 3.2 seconds
-desired EGR command greater then 40%
-MAP above 47.5 kPa or less then 15 kPa.

The computer monitors the EGR effectiveness by momentarily de-energizing the EGR solenoid which shuts off the vacuum to the EGR valve. With the EGR closed, the fuel integrator counts must fall within calibrated window that is greater then during normal EGR operation. (The Mixture called for must change an expected amount). After failing the test twice a code 32 will be set.

For those of you that are wondering why you are not getting replies to your thread:

Did you give the model, year, engine, fuel system type, and transmission information?

If the it has been altered from stock let us know about that too.


 
Algoma56 
Contributor
Posts: 645

Loc: Sault Ste. Marie, ON, Can...
Reg: 03-14-05
01-25-08 02:44 PM - Post#1351102    
    In response to Stefan E.

My 88 305 used to trip the light intermittently. If I ran down a long hill at highway speed, (high vacuum), light would come on after a minute of this. It would go out after about 4 or 5 minutes of steady state driving, most times. I checked the EGR, and seemed to work okay, EGR solenoid was replaced. I beleived it was buildup in the intake port for the EGR causing the problem, but never did find out as I sold the truck. (Not because of the EGR, I bought a newe ext cab)

 
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