2002 Chevy Tahoe Sercvice Engine Light

JOHNNYPOPPER

MEMBER
2002 CHEVROLET TAHOE
V8
4WD
AUTOMATIC
136,000 MILES

Service Engine Light came on last night - same time as the clock on the radio reset to 12:00. Radio pre-sets did not change.
Engine is running fine and no other accessories or lights seem to be affected.
Took it to Auozone to pull the ODBII code, but there was no power to the connection plug under the dash.
Guy said it might be a fuse problem keeping the plug from relaying the trouble code, but I can't find a fuse for the PCM anywhere! What would cause the plug to be unpowered but not make the engine run rough?

Help!

3 Replies

SERVICE WRITER

MECHANIC
9,123 POSTS

Communication between the DLC and the computer is your first problem....after you establish communication, find the codes and post them.
The cigar lighter and the DLC are on the same fused circuit. No communication will not affect anything other than the communication.

!5 amp, on the cigar fuse #47 in the underhood fuse box.

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Saturday, January 24th, 2009 AT 8:50 AM

JOHNNYPOPPER

MEMBER
3 POSTS

Your tip and diagram led me right to the fuse I was looking for and we got the code pulled.

It was P0332 which looks like a knock sensor has either gone bad or lost connection.

Will harm come to the engine if I can't get this taken care of in the next two weeks?

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Saturday, January 24th, 2009 AT 6:02 PM

SERVICE WRITER

MECHANIC
9,123 POSTS

Okay we are getting closer to the solution.

Pull the intake and inspect the knock sensors.If both
are rusty or corroded from swimming then replace both. If only the sensor setting the code is crusty,then replace only that sensor.Then build about a quarter inch dam all the way around both sensors with RTV so that water will run around the sensor holes instead of in them.

Here is a tsb that details it a little more:

IF it is going to be a couple weeks, I would run high octane until the repair is done to minimize any pinging if it is happening. I don't see it being a big deal to wait a couple weeks...but if pinging is happening it can cause a headgasket failure.

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Sunday, January 25th, 2009 AT 8:53 AM