Battery Shorted and High Current Array Blown

[cosunrise]

2018 JL e torque here. Had no start condition yesterday (push button, no crank). Tried switching the bypass on and off, charging main battery both ways. Eventually pulled the battery to bench test but something shorted in the process, electrical odor and discovered today that N6 in the high current fuse array, which is EHPS, was down. All other fuses in the array tested good. Replaced the fuse array.

It starts now, but radio unit is dead/no power, power steering and battery lights and displayed, my Tazer doesn't work and has no lights, and ODB2 pulls these codes.

P0A94
P0C78
P0480
P0480-F0
U0415
U1003
U0100
U1818
U0131
U1159
U0159
B21DD-84
C212A-16
U0485
C151C
C2205-2F
P1B13

Where should I start? Seems like maybe can buss?

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[ScotM]

That’s a lot of codes. First thing I would try, is clear all the codes, then cut power to the jeep overnight. Then hook everything up and see what is working . Once power is restored, it can take up to 24 hours for everything to come back to normal. If that doesn’t work, either panic at your leisure or drink. I hope others have better solutions.

 

[cosunrise]

Thanks. Whatever circuit the Tazer connects to isn't working. I pulled the Tazer out and tested it via USB and it is fine, so must be something in the circuit. Can't clear codes until that's fixed because security gateway prevents ODB2 from writing data/clearing codes.

 

[gato]

Given that you had a major short, you need to start by verifying the electrical system.

1 - Clear all codes (as mentioned above). Go through 2 complete off, lock, exit, let all lights shut off cycles. Reclear, reread the codes. That will be a true post fault read out. Check battery health.

2 - Recheck the high amp fuse array, the battery/ground connections and voltages *and* (all) the fuses related to the fault codes. You may have several blown fuses.

3 - The fact the vehicle starts and runs is a good sign that the ECU and engine related circuits (fuel, etc) are good. But for the systems still down (e.g. EPS) it will be detective work one by one. (It is unlikely that it is a generalized high speed can bus issue - if your auto transmission shifts into gear, there is at least a fair amount of CAN messages flowing.

4 - Good luck. You will get through it.

 

[gato]

Thanks. Whatever circuit the Tazer connects to isn't working. I pulled the Tazer out and tested it via USB and it is fine, so must be something in the circuit. Can't clear codes until that's fixed because security gateway prevents ODB2 from writing data/clearing codes.

If you buy a Launch scanner (~$120 on Amazon) or any other more professional scanner with brand specific downloadable module, they will register with the secure gateway and be able to clear codes without a bypass.

 

[cosunrise]

Thanks; I had a Jscan compatible reader on the way anyway, so that should be here today and I'll clear/rescan.

If my research is correct, it looks like power flows directly from the N6 high current fuse to the power steering pump, so the "service power steering" warning on the display when the start button is pushed likely indicates pump failure? The only other related fuse I can find is the control circuit on fuse 34, and that fuse tests good.

Fuse 97 was blown and replacing it restored the radio/nav unit.

 

[gato]

TFuse 97 was blown and replacing it restored the radio/nav unit.

There you go. One down, maybe a few more to go.

If my research is correct, it looks like power flows directly from the N6 high current fuse to the power steering pump, so the "service power steering" warning on the display when the start button is pushed likely indicates pump failure?

After you start the Jeep do you have power steering or is it hard to turn?

It's possible that the pump got damaged by the short, but not as likely as it needing a few power-down cycles, battery disconnect or some issues in the control signal. May be worth digging some more.

 

[cosunrise]

Yeah, there's definitely no power steering. It's very hard to turn.

Got my Jscan, read and cleared codes, 2 sleep cycles, re-read and re-cleared codes. Still active codes for

P0A94-00 DC Converter Performance
P0A94-05 DC Converter System Programming Failure
U0131-00 Power Steering Control Module
P0480 Cooling Fan Circuit Open

There are also a couple of codes about Lockers and TPMS, but those were there before as I did an axle swap and installed new TPMS sensors, so I believe they are unrelated.

 

[cosunrise]

Checked all fuses and everything tests good, resistance and continuity.

My theory is that the main radiator fan, the power steering pump, and the MGU fried, resulting in the codes above. I've tried applying 12 volts to the fan circuit and nothing, power steering has a control circuit so it's not as simple to test. I ordered replacements for the fan and the power steering pump and will swap when they arrive.

I understand that the MGU (68432441AD), if purchased new, needs to be programmed at a dealer. However, I've located one at a salvage yard. This may deserve or require it's own thread, but does anyone know what the dealer flashes the MGU with? Would a used one from donor that's already programmed work, or is it VIN specific, etc?

 

[gato]

Checked all fuses and everything tests good, resistance and continuity.

My theory is that the main radiator fan, the power steering pump, and the MGU fried, resulting in the codes above. I've tried applying 12 volts to the fan circuit and nothing, power steering has a control circuit so it's not as simple to test. I ordered replacements for the fan and the power steering pump and will swap when they arrive.

I understand that the MGU (68432441AD), if purchased new, needs to be programmed at a dealer. However, I've located one at a salvage yard. This may deserve or require it's own thread, but does anyone know what the dealer flashes the MGU with? Would a used one from donor that's already programmed work, or is it VIN specific, etc?

You may want to look into the DC Converter error codes and Power Steering Control Module vs the Steering Pump.

Do you have an etorque model?

I see a TSB with those symptoms....posting here for you in case there is any good info that can help point you in the right direction.

Good luck with your troubleshooting.

https://www.jlwranglerforums.com/fo...trol-module-bpcm-updates-march-16-2019.34619/
(see the attached TSB in this thread)

 

[entropy]

That’s a lot of codes. First thing I would try, is clear all the codes, then cut power to the jeep overnight. Then hook everything up and see what is working . Once power is restored, it can take up to 24 hours for everything to come back to normal. If that doesn’t work, either panic at your leisure or drink. I hope others have better solutions.

Overnight? How is OP going to get any sleep

 

[cosunrise]

I can't find anything about a separate power steering module. I thought it is integrated in the electric power steering pump itself?

 

[roaniecowpony]

Checked all fuses and everything tests good, resistance and continuity.

My theory is that the main radiator fan, the power steering pump, and the MGU fried, resulting in the codes above. I've tried applying 12 volts to the fan circuit and nothing, power steering has a control circuit so it's not as simple to test. I ordered replacements for the fan and the power steering pump and will swap when they arrive.

I understand that the MGU (68432441AD), if purchased new, needs to be programmed at a dealer. However, I've located one at a salvage yard. This may deserve or require it's own thread, but does anyone know what the dealer flashes the MGU with? Would a used one from donor that's already programmed work, or is it VIN specific, etc?

The fan is a PWM speed controlled motor. Putting 12v to the motor (plus the ground) probably won't do anything with such a motor, without the pulse wave third wire providing speed control. You can check, but likely you have 12v at the fan motor connector near the radiator/intake tube on the big wire. The small gauge wire is the PWM signal.

If you haven't already, go through your entire power distribution center and check each fuse (just use some pointed probes on a multimeter on the top of each fuse, where there are little holes), then pull each relay and check function and continuity (jumper 12v pigtails across the solenoid circuit and continuity on the relay circuit). Then check for power to each socket and write down which circuits don't have power. This may help you later.

 

[cosunrise]

There is 12v at the fan motor connection, but unfortunately replacing the fan did not resolve P0480, cooling fan control circuit open.

All fuses and relays re-checked good.

 

[roaniecowpony]

I would move on to checking the PCM forward connector (gray) . I have some basic power checks that @alphawolff provided to me. Since you and I both have 2018s, I'm assuming your PCM is the same or similar GPEC2A configuration. This should establish whether the PCM is getting basic power/ground and CANBUS signal.

Here's the link to my effort last year where @alphawolff helped me.
(2) New Engine Install - Rough start then Stalls | Page 3 | Jeep Wrangler Forums (JL / JLU) -- Rubicon, 4xe, 392, Sahara, Sport - JLwranglerforums.com

In that thread, @alphawolff had me do some tests for power and comm signal in the PDC as well as the PCM connector. I made some test pins for the PDC tests by using fuses and just cutting off one leg. For the PCM connnector, I measured the pins on the PCM itself and made a test probe and pin drag tester by grinding an exacto blade of the same thickness to shape. Don't forget to round the tip and polish it a bit to prevent damage to your harness connector. Some of the probes are in the thread linked above.

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