2003 Tahoe shuts off randomly

Joseph Garcia

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Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving sage advice from the knowledgeable folks on this Forum.
 

rockola1971

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All of the P codes listed have to do with wrong voltages deteced in the DBW system. This is going to be a tough one to troubleshoot without a scanner and a extra set of hands to wiggle stuff to narrow down where the possible loose connection or wiring problem is. The reference voltage for most sensors on the engine is 5v. This volatge can easily be lowered or even spiked to cause a false code depending on what the electrical fault is that may or may not be related to the DBW system. I just have never seen a DBW fault cause a total engine shutdown. Its interesting that you are not getting a reduced engine power mode and engine reverts to idle speed only. That all leads me to believe you have a loose or corroded conenction or maybe even a wire(s) that has insulation rubbed through and touching ground like MassHoe04's For Ranger above.

When the DBW faults you will get that reduced engine power mode and the PCM will put the engine speed at Idle immediately and no matter what position you have the throttle pedal at the engine remains at Idle. Have you seen any of that happen on this Tahoe?
FYI- I have Two 2003 Tahoes both Vin Z with the Flex Fuel so I can go out to my driveway and compare stuff for you.
I highly recommend that your relative or maybe you invest $300 in a GM Tech 2 clone. It will more than pay for itself. GM or a garage would charge well more than $300 alone to troubleshoot and fix this problem on the Tahoe.

First I would run to all the major Ground wires and Positive wires and disconnect and clean them then retighten. Make sure all ground connection are free of corrosion especially down at the starter and at the battery. Dont forget to check the positive "jump start" connection on drivers side between battery and engine down low. Then Test again to see if fault remains. Check positive charge wire connection at the rear of alternator also.

I dont want to totally steer you away from the DBW system so check at the Throttle Body too for broken wires at the wire plug in to the Throttle Position Sensor. You may not be able to actually see a broken wire there because of the insulation but you usually can feel it. The breaks usually happen within 6" of the plug. Feel each wire and wiggle as you run your fingers down them and if there is a break you will feel the difference between a good wire and a bad wire. It will stick its ugly head out at you.
 
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Gavin Strunk

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Hey guys sorry for not replying in almost a month, it seems like things have been very busy lately. So there was sketchy looking electrical tape around the wiring that plugs into the throttle body. I untapped and then used new electrical tape to redo that. Then I unplugged the throttle body and plugged it back in. It hasn't had its problem since. Can't believe that actually worked but it did, it's probably gone 500 miles with no issues. I ended up buying it as a second vehicle or beater unit. I put new brakes on and tires are next. This unit has 295k miles and isn't in the best shape but it still runs and drives pretty decent. For cheap it was totally worth it so I can keep my 14 Silverado out of the college parking lots lol.
 

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