1999 GMC Suburban REPEATED SERVICE ENGINE SOON LIGHT

GRAY74

MEMBER
1999 GMC SUBURBAN
V8
4WD
AUTOMATIC
111,788 MILES

99 GM Suburban has been in repeatedly for service engine soon light. Replaced OE MAF sensor twice and cam position sensor. Drive vehicle less than 10 miles service engine light comes on. Taken back in, initially no codes come up, light is still on. Wiring checked, replace pig tail to be sure, smoke tested for vacuum leaks, ok. Try to pull codes again, downstream 02 sensors replaced. Light coems on again. Vehicle taken to dealer, new computer installed, drive car 40 miles, light back on.I am completley frustrated and dont now what to do know as both my local shop and dealer are dumbfounded. Could it be that the new cpu is picking up additional issues such as the other two 02 sensors?

Sunday, August 9th, 2009 AT 12:41 AM

3 Replies

BRIAN 1

MECHANIC
1,030 POSTS

What were the codes?Post them and will advise.

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Sunday, August 9th, 2009 AT 9:22 AM

GRAY74

MEMBER
4 POSTS

I just got back from Autozone and they pulled 3 codes: P0102, P0172, and P0175.

Do I now have an injector problem?

Thanks-Gordon

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Sunday, August 9th, 2009 AT 10:25 AM

CAPECOD88

MEMBER
3 POSTS

We have had the same issue, the light comes back on after its cleared. The codes are not 'true', there is nothing wrong with the Suburban.
We even changed the computer, and now the light stays on longer.
Nothing at all wrong with the entire vehicle.
Even the repair shop cannot solve it, though they know its a 'known issue'.
So what to do?
You ignore it, and if you have to get an inspection sticker like we do here in Taxachusetts, the tech will clear the light, do the inspection. Then the light will be back on by the time we get home.
No fix to it. Ignore it.
Hope this helps.

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Thursday, March 4th, 2010 AT 7:21 AM