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Losing engine gauges, speedo, and fan staying on - Mrkentee - 05-24-2025
Driving along and lost gauges, and fan came on and stays on.
Took abs fuses out and ran fine. Thought I had it figured out until I got home.
Started doing it again. Put jpro on and confirmed abs faults.
Disconnected every abs and removed fuses. No help.
It comes back for a while if you’ve been sitting, and is slightly sporadic.
When happening get low voltage at diag plug.
When working voltage and resistance are perfect.
I’ve checked everything I can think of. All the wiring I can get to.
I’ve had some codes on my elog for bad intelligent device, and abs, and cab controller.
The elog is affected by the low voltage at the ecm plug, so it’s probably not the cab controller. That’s also why my inline 5 wouldn’t connect.
I can drive it, but no gauges and the fan stays on.
I’m wondering if it might be the ecm, but the engine runs fine.
2010 Peterbilt 386
RE: Losing engine gauges, speedo, and fan staying on - Colter - 05-24-2025
It should be communication issue between ECM and CAB. Low voltage at the power pin in the 9PIN or the J1939 voltage?
If you have ESA you can connect to CECU and check for any code listing a CAN line failure. These issues are usually outside the cab under the hood, I would start by finding the blue resistor plug in the OEM harness along the drivers side of the valve cover. It'll have blue/yellow wire pair in and out of it. There may be a loose pin or a rub somewhere in that wiring.
Peterbilt also tend to get rubs in the ECM power supply but the symptoms don't really match that, I'd assume your hours and KM go to dash's when the issue happens as well?
RE: Losing engine gauges, speedo, and fan staying on - Mrkentee - 05-24-2025
(05-24-2025 )Colter Wrote: It should be communication issue between ECM and CAB. Low voltage at the power pin in the 9PIN or the J1939 voltage?
If you have ESA you can connect to CECU and check for any code listing a CAN line failure. These issues are usually outside the cab under the hood, I would start by finding the blue resistor plug in the OEM harness along the drivers side of the valve cover. It'll have blue/yellow wire pair in and out of it. There may be a loose pin or a rub somewhere in that wiring.
Peterbilt also tend to get rubs in the ECM power supply but the symptoms don't really match that, I'd assume your hours and KM go to dash's when the issue happens as well?
Low volts at the J 1939 connector on the lower left will you connect your diagnostic equipment. Yes mileage and hours go to dashes, as well as elog can’t tell anything. I don’t see any problems with the wiring in the front, but I haven’t ripped the whole thing apart. I did look at that Resistor and it looks OK. Right now it’s working for about the last 40 minutes except in for a couple minutes. I guess if it is a wire problem, I’m just gonna have to dig it and try and find it.
No, I don’t have ESA. I only have an in-line five, and insight. I have calt$rm, but I don’t know how to use it unfortunately. I really need to learn.
RE: Losing engine gauges, speedo, and fan staying on - Rawze - 05-24-2025
tarnished fuses in the fuse panel?.
RE: Losing engine gauges, speedo, and fan staying on - Mrkentee - 05-24-2025
(05-24-2025 )Rawze Wrote: tarnished fuses in the fuse panel?.
I replaced them all about a year ago. Would that cause something like this?
RE: Losing engine gauges, speedo, and fan staying on - Mrkentee - 05-24-2025
(05-24-2025 )Rawze Wrote: tarnished fuses in the fuse panel?.
I think you’re on to something. I was able to duplicate all the symptoms by pulling a couple of different fuses. I think that fuse box needs some attention.
It was so wet out the last few days when this started. All that dampness.
I’ll know better tomorrow when I take off.
RE: Losing engine gauges, speedo, and fan staying on - Colter - 05-26-2025
Do you have a 1117 code on the engine side? That would confirm power issue which is not abnormal but i don't think its the right direction.
If someone on your behalf could plug in with ESA that would be beneficial and can narrow the issue down in case there is something on the IP side causing problems. Unfortunately without an active issue if tough to find. I wouldn't recommend tearing wiring harnesses apart, stick to points where its tied up or braced, cut ties and check for rubs.
RE: Losing engine gauges, speedo, and fan staying on - Mrkentee - 05-26-2025
(05-26-2025 )Colter Wrote: Do you have a 1117 code on the engine side? That would confirm power issue which is not abnormal but i don't think its the right direction.
If someone on your behalf could plug in with ESA that would be beneficial and can narrow the issue down in case there is something on the IP side causing problems. Unfortunately without an active issue if tough to find. I wouldn't recommend tearing wiring harnesses apart, stick to points where its tied up or braced, cut ties and check for rubs.
No, don’t have that code at all. I have no active codes. From when it was acting up, I have 2 inactive, J 1939 multiplexing, and ABS abnormal update rate. At one point, I disconnected the entire abs system, and pulled the fuses, and it didn’t help. Prior to that my shop guy checked it with Acom, and found two active abs codes.
It definitely seems like a fuse problem. It’s been fine for 2 days. I replaced some fuses, and gave the fuse panel a good look over.
My elog gives me codes, also. They are different than what Insite says. See picture. But those elog codes have been around for ever. I don’t pay much attention to it, or really trust it.
That’s all I know right now. I’ve pulled and yanked on every wire and bundle I can find, and nothing changed.
[attachment=9889]
With Acom-[attachment=9890]
RE: Losing engine gauges, speedo, and fan staying on - Colter - 05-27-2025
This would be a fun one to find, elogs are always terrible at codes, I assume one tank guage isnt working. Without a 1117 you ECM power supply should be good, the fact the the ABS seems to be flagging a voltage issue opens up the rest of the wiring.
Just for giggle does your battery box have a fusible mounted at the rear with a smaller cable? If so is it corroded? Also when it does rear its head does your voltage guage do anything weird?