Red stop engine light keeps coming on. 99 379 pete

Discussion in 'Truck Maintenance and Repair' started by corneileous, Apr 20, 2017.

  1. corneileous

    corneileous Active Member

    Hey guys, got another issue on the ole Pete again that's being a real

    Anyway, 99 379, M-11 Cummins. The problem is, and it does it completely at random, is the red stop engine light comes on and the throttle is unresponsive. Not sure if there's a connection or if it's just something that's just completely coincidental but pressing down and fully releasing the throttle seems to "wake" the truck back up. So far the only time it seems to throw the stop engine light and not respond to the throttle pedal is when throttling back up after coming off from coasting.

    The things my shop has done so far to try and fix this has been, #1, they thought maybe the throttle sensor on the pedal was bad so they replaced it. That seemed to make the issue worse. Then they found one of my fuel injector wiring harnesses wasn't plugged all the way in. Again, wasn't it. Then they decided to replace the whole inner fuel injector harness under the valve cover... that of course, wasn't it. lol. Last thing they've done now was to get an outside, local mechanic to come over and take a look who has a laptop. He found that the throttle sensor wasn't communicating with the ECM correctly and that it needed to be calibrated. Present day, the stop engine light has already come on 4 times today.

    Y'all have any input on what might be causing this?

    Thanks in advance for any help.
  2. fastlane mclain

    fastlane mclain New Member

    Have cummins plug it in. It took me taking my truck to cat to figure it out i replaced cam sensor crank and throttle position sensor ended up my wiring harness was frayed and kept grounding out
  3. GAnthony

    GAnthony Well-Known Member

    go to a better shop, where someone actually knows how to work the scanner. seems like they are just assuming what is wrong..

    this a company truck or o/o truck..???

    if an o/o truck, your sir, are being taken for en expensive ride.....

    company truck..??? let'em play with themselves, as that's the most experience they got.
  4. corneileous

    corneileous Active Member

    Thanks for your reply.

    Yeah, it may perhaps lead to a meeting with the mobile Peterbilt mechanic around here to figure it

    Hmm. What was the problem you were having and which wiring harness was it?
  5. corneileous

    corneileous Active Member

    First off, I like your Had a little bit of a chuckle. lol.

    But yeah, it's a company truck. If it was mine, I would have taken it to Peterbilt and had them look at it long time ago. I'm at the mercy of what the boss wants to do.

    Our shop just gets us by for the most part but at least the boss is working on getting them a laptop with all the cables and the software so they can properly diagnose these trucks. They have a little glorified code reader scanner but in my opinion it's about as redundant as a screen door on a submarine.

    I thought this time for sure that they'd figure it out with that outside mechanic that had a laptop but guess not.
  6. corneileous

    corneileous Active Member

    Another thing, even on this age of a truck, is this stop engine light like a "limp mode protection" for any kind of problem or could it just be something on the other end of the spectrum and be something between the throttle pedal and the ECM?
  7. GAnthony

    GAnthony Well-Known Member

    i worked for a guy that owned some trucks, he too did what "just got him by"...

    he is long gone out of business.. a **** poor owner/boss, is going to cost YOU time and money, when you sit on the side of the road.

    common sense would dictate, he take the truck(s) for scanning at the Cummins dealer/shop.

    less money actually spent, in the long run..

    good luck.
  8. corneileous

    corneileous Active Member

    Well, I'm gone get to meet with the Peterbilt guy early this afternoon so maybe he'll be able to figure it out. Plus I'll be there to ask questions and raise other ideas about what all it could be. The only time I was present during any repairs was when they found that injector harness that "supposedly" wasn't plugged in all the way.

    Wish me luck.
    • Like Like x 1
  9. GAnthony

    GAnthony Well-Known Member

    • Like Like x 1
  10. corneileous

    corneileous Active Member

    Well, I guess for now we got it figgered out. Not sure if it's the right way or not but, they ended up snipping one of the wires to the other switch on the pedal, the one that tells the computer when it's idling.

    Apparently they put the wrong throttle switch on long time ago. Apparently because of that, both switches were telling the computer their information at the same time when they're not supposed to. That's supposedly what was causing the stop engine light.

    Like I said tho, not sure if it was the right way or not but, I'm just informing that what they did, worked. Been driving it for three days now and the light hasn't been back on. Truck idles and drives how it's supposed to. Cruise still works, high-idle still works, pedal cancellation still works.... Never would know anything was different.
  11. mndriver

    mndriver curmudgeon extraordinare Staff Member Supporter

    I'd be pissed if their "fix" was to start hacking the wiring harness when it was due to an incorrect part being installed.

    get the right part and fix it correctly.

    What's going to happen the next time someone goes in and fixes it and puts the correct throttle sensor in and now with that cut wire, it's not functional?

    Just my opinion.

    That and $5 will get you a coffee at Starbucks.
  12. corneileous

    corneileous Active Member

    Yeah I know but you gotta understand how our shop works. Lol. But yeah, it shouldn't have taken a whole lot to notice that the wires on the new switch were not in the same order as the switch they replaced.

    As I said, it works and I'm tired of dealin' with it and swapping trucks.

    But, if the boss ever sells that truck, it shouldn't be too hard to fix if it ever created a new problem down the road. The other day when I said I was going to meet with the mobile Pete mechanic, he ran all new wires from both pedal sensors to the computer thinking that a rubbed wire mighta been the problem.

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