2003 Denali will not start- no clicking - has power

dave in kelsey · August 17, 2013

My wife was driving on the freeway when a message popped up, "Service Stability Sys" and then it died. She had it towed home and we're checked the fuses and relays. Battery is hooked up and tight and from what I can see without digging, the wires are good.

I played with the tilt and the key and I can't get any signs of power getting to the starter. The power does cut out when I try to start the engine. Besides hunting down a loose ground wire or grounded power wire, is there anything else I should be looking at?

On a side note, I plugged in my scanner tools even though the check engine light never came on. Both of them fail to connect. One of them says I don't have the ignition on. I also tried starting it in neutral to see if the safety switch was toast.

Background: 2003 Denali with 156k miles. gauge cluster replaced, MAF, intake gaskets, tranny, and both front hubs.

scooby5121 · August 17, 2013

Check for power at the starter....

Try hitting the solenoid on the starter while someone turns the key........ with a hammer.

If not able to read codes, normally it means your battery is toast. Not enough power to run even the diagnosis.

or a poor alternator that did not keep the battery charged.

I would start with the obvious.... power problem.

Scooby

dave in kelsey · August 18, 2013

The battery is less than 6 months old. I stuck it on the charger just in case. I hooked it back up... same thing. All the connections look good. Another odd thing I noticed, the average mpg, oil life, miles left will not display. The only thing that shows is the overall mileage. But I'm not sure if that gets wiped out when I disconnect the battery for a long period of time. I can always pull one of the batteries out of my truck to triple check.

Since the battery had and still does have a full charge, I don't think it's the alternator. That leaves the wiring down to the starter, inside the dash, and the computer.

What are the signs of the computer dying?

govener71 · August 18, 2013

I had something similar on my 99. Thought it was a relay, ended up being the positive wire inside the shield on the starter. Everything worked fine but would not start. Stupid wire left me stranded in ap parking lot. Only difference though is you said your wife had it cut out while driving...... That's the part that makes me think its not the starter.

gmtech4 · August 18, 2013

test light at the starter purple wire while ya turn the key ,,,,,if it lights ,,and battery is 100% ,say g'by to starter

Document ID: 868768

Starting System-Gas

dave in kelsey · August 18, 2013

I'll see if I can get it up on jack stands and test that wire. There is a large fire in the area and the smoke if really bad today.

I guess if the power wire is grounded out it would kill the engine, but normally a dead starter wouldn't kill a running engine.

I don't like the fact that the code readers wont connect. I'm going to play with the relays some more and maybe borrow one from my truck if its the same.

dave in kelsey · August 19, 2013

I found it. It was the 20 amp fuse to the PCM. Not sure why that would blow..

NEFisher11 · August 19, 2013

Dose the truck have Passlock by chance? I had a Colorado that had Passlock and it acted up and i couldn't start the truck.

NVM saw that you fixed it.

dave in kelsey · August 26, 2013

Well.. its happened again. At least my wife knew what to do. Thank you for posting the diagram of the circuit, but I really can't tell what else is on that 20amp circuit. My guess it's the PCM but before I drop a few hundred bucks I want to be sure. I called the dealer and they want $120 to hook it up and track it down. $563 for the PCM minus the coding.

PhilB · August 26, 2013

This sounds similar to what a friend had on his 2001 Yukon Denali. It would die while driving and wouldn't restart. Then later it would work fine. After replacing the battery and alternator, a mechanic found that the small red wire going from the battery to the junction block had issues. Nick or short I don't remember. But they replaced it and no more problems. Something to think about.

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