Battery Shorted and High Current Array Blown

[cosunrise]

So, I decided to swap front left and right wheel speed sensors. The code followed from left to right wheel, so I bought a third front sensor, installed it, and the code cleared. Apparently I had two bad ABS sensors?

ABS errors went away... Until I started driving, and quickly popped the C0037-62 (left rear wheel speed sensor-signal compare failure) and another couple of general ABS codes, U0415 and U0418.

I'll chase that one down tomorrow, but after taking her for a drive, I have a host of new codes to get feedback on:

U1003-00 ESP CAN C BUS Performance
U11C2 Implausible/missing transmission message
U110A Lost communication with SCM - CAN C
U1412-00 Implausible vehicle speed signals received (TCM)

And I still have that pesky P0480 rad fan control circuit code as well.

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[alphawolff]

I have 11.9 volts at the ABS sensor.

Would indicate a failed sensor or failed module

edit; see you isolated the sensor. good work

 

[cosunrise]

In pursuit of the cooling fan code P0480, coolant temp sensor tested good but for $10 I replaced it to be sure. No impact on the rad fan code.

Established continuity between PCM AND read fan, which runs through multiple connectors the long way around the engine bay from front left back to the firewall, over and back up the passenger fender and grille to the cooling fan. As far as I can tell, there are no fuses or relays involved with the rad fan except for the high current fuse array at the end of the PDC.

Does anyone know whether the control wire/circuit is energized at run, or only when the PCM is requesting cooling? Also, there's only one control wire running to the rad fan, so how does the PCM even know/detect/think that the circuit is open or shorted?

Just trying to determine next steps that hopefully don't include replacing the PCM.

 

[roaniecowpony]

Did you try turning on the a/c to see if the fan runs? It should run on a/c command. At idle

 

[cosunrise]

Oh, OK. It does not. I thought it had to exceed 200F even with A/C, but I had it at 192F at idle with A/C and the fan did not run.

 

[roaniecowpony]

Oh, OK. It does not. I thought it had to exceed 200F even with A/C, but I had it at 192F at idle with A/C and the fan did not run.

I don't think it needs 200F. My fan comes on when it's cold when the A/C is turned on. But, I have a RPM Extreme fan controller. But, I believe others have said the fan comes on. Someone else will have to verify.

 

[mwilk012]

In pursuit of the cooling fan code P0480, coolant temp sensor tested good but for $10 I replaced it to be sure. No impact on the rad fan code.

Established continuity between PCM AND read fan, which runs through multiple connectors the long way around the engine bay from front left back to the firewall, over and back up the passenger fender and grille to the cooling fan. As far as I can tell, there are no fuses or relays involved with the rad fan except for the high current fuse array at the end of the PDC.

Does anyone know whether the control wire/circuit is energized at run, or only when the PCM is requesting cooling? Also, there's only one control wire running to the rad fan, so how does the PCM even know/detect/think that the circuit is open or shorted?

Just trying to determine next steps that hopefully don't include replacing the PCM.

The comm wire uses a PWM signal and shares a common ground at the fan. All else being good, it sounds like it fried the PCM’s output circuit. Continuity check the one comm wire, double check the power at the fan being good, trace ground to the frame, Replace PCM. Do you have an oscilloscope?

 

[cosunrise]

I don't have an oscilloscope currently. This could be an excuse to get one...
But, I'm hung up on the fact that I can activate the fan manually through the PCM in Jscan. As I understand it, if the output circuit was fried, the PCM wouldn't be able to turn on the fan, and modulate fan speeds, either through it's own programming or through Jscan. I can do both on demand in Jscan.

 

[mwilk012]

I don't have an oscilloscope currently. This could be an excuse to get one...
But, I'm hung up on the fact that I can activate the fan manually through the PCM in Jscan. As I understand it, if the output circuit was fried, the PCM wouldn't be able to turn on the fan, and modulate fan speeds, either through it's own programming or through Jscan. I can do both on demand in Jscan.

Hmm more testing is certainly needed then. How quickly does the fan control circuit fault return after clearing? Did you replace the fan with an OEM?

 

[cosunrise]

The fan code doesn't clear. It's immediately there upon re-scan after clearing.
Yes, replacement fan is also OEM.

 

[cosunrise]

Thanks for everyone's help on this.

I finally pulled the wheel and brakes and found the air gap on the LR wheel speed/ABS sensor was 3-4mm (way to large). Shimming the one side of the sensor put the sensor face about 1mm away from the tone ring, buttoned everything back up, and no more C0037-62, U0415 or U0418.

That was the big barrier to passing my state VIN inspection (all safety systems need to be working), so I took a chance and drove her from Denver to Colorado Springs yesterday for the inspection. Stopped a couple of times along the way as I'm also breaking in new gears.

Pulled codes when I arrived for the inspection and the rad fan code P0480 as well as the Bus related codes U1003-00 and U110A were gone. Not sure why Jscan wasn't able to clear but apparently a couple of longer drive cycles did the job.

However, (nothing is ever that easy, right), the Jeep was ridiculously sluggish and bogged down on the slightest incline. I was on back roads due to breaking in new gears and didn't want to exceed 55-60mph, and although there are no mountains between Denver and the Springs, she could not maintain 55 on the slightest incline. RPMs spiked to 4500+ but she just kept losing speed from 55 to the low 40s before cresting the hill, and she'd be fine until the next incline. Shifting from 1/2/3 was also really rough, with the Jeep holding the lower gear and then really throwing into the next higher gear with a lurch. (This sounds like extraneous info, but wait for it.)

Having no eTorque experience, my mind went to plugged cat, but there are no codes, which seems highly implausible. Doing a little reading on the forum, though, it sounds like the 2.0l relies heavily on e-assist from the BAG/MGU in incline scenarios like this, and without it the Jeep really bogs down. eTorque is evidently also used from a stop through the first few gears. Without assist folks say it's super rough as the Jeep is looking for e-assist that isn't there.

All that said, there is almost zero troubleshooting info on the forum or interwebs as a whole regarding the 2.0l eTorque system. Any starting points for determining if/whether my brand new MGU/BSG is actually providing e-assist when it's supposed to? Or why it feels like a moped?

 

[Wabujitsu]

Thanks for everyone's help on this.

I finally pulled the wheel and brakes and found the air gap on the LR wheel speed/ABS sensor was 3-4mm (way to large). Shimming the one side of the sensor put the sensor face about 1mm away from the tone ring, buttoned everything back up, and no more C0037-62, U0415 or U0418.

That was the big barrier to passing my state VIN inspection (all safety systems need to be working), so I took a chance and drove her from Denver to Colorado Springs yesterday for the inspection. Stopped a couple of times along the way as I'm also breaking in new gears.

Pulled codes when I arrived for the inspection and the rad fan code P0480 as well as the Bus related codes U1003-00 and U110A were gone. Not sure why Jscan wasn't able to clear but apparently a couple of longer drive cycles did the job.

However, (nothing is ever that easy, right), the Jeep was ridiculously sluggish and bogged down on the slightest incline. I was on back roads due to breaking in new gears and didn't want to exceed 55-60mph, and although there are no mountains between Denver and the Springs, she could not maintain 55 on the slightest incline. RPMs spiked to 4500+ but she just kept losing speed from 55 to the low 40s before cresting the hill, and she'd be fine until the next incline. Shifting from 1/2/3 was also really rough, with the Jeep holding the lower gear and then really throwing into the next higher gear with a lurch. (This sounds like extraneous info, but wait for it.)

Having no eTorque experience, my mind went to plugged cat, but there are no codes, which seems highly implausible. Doing a little reading on the forum, though, it sounds like the 2.0l relies heavily on e-assist from the BAG/MGU in incline scenarios like this, and without it the Jeep really bogs down. eTorque is evidently also used from a stop through the first few gears. Without assist folks say it's super rough as the Jeep is looking for e-assist that isn't there.

All that said, there is almost zero troubleshooting info on the forum or interwebs as a whole regarding the 2.0l eTorque system. Any starting points for determining if/whether my brand new MGU/BSG is actually providing e-assist when it's supposed to? Or why it feels like a moped?

I’m lost on this, and following with fascination. All I know is I have a 2.0T without eTorque and it does not bog down on mountain inclines.

 

[gato]

However, (nothing is ever that easy, right), the Jeep was ridiculously sluggish and bogged down on the slightest incline....

it sounds like the 2.0l relies heavily on e-assist from the BAG/MGU in incline scenarios like this

The eTorque can at best give you 1/2 sec to 1 1 sec of assist starting from a stop or to smooth out gear changes. There is no way the eTorque plays a role going up an incline at a steady 55MPH.

If I were to guess, I'd say that your Turbo wastegate controller is fried and it is dumping all the boost (assuming you checked and don't have any fried coils or plugs). You have a major power loss if you can't maintain 55MPH on a light incline - as in your engine is likely not even making 100HP.

P.S. - Since you mentioned new gears, the other possibility is a major fouled up wrong or binding gear set.

 

[cosunrise]

Thanks @gato.

The Internet suggests that the PCM limits spark, boost and torque output when there is no assist from the DC/DC Converter.

I'll take a look at the turbo wastegate, but wouldn't that throw a code also for low boost or no boost? I know there is a boost sensor.

 

[Terrymo]

Here’s a simplified explanation of the etorque system in case you haven’t already seen it
https://www.jlwranglerforums.com/fo...e-what-it-is-how-it-works-what-it-does.74400/

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