Mastiff

I have less than two weeks and 500 miles on my new JK. I started out on a trip today and the engine light came on. Went to O'Reilly and had them read the codes for me:

P0507 - Something to do with idle air control, RPM higher than expected
U1412 - ? Maybe something to do with speed sensor ? Can't find it listed

He cleared the codes and I went about a mile down the road when it started stumbling and two dash lights came on, one for electronic throttle control and one for electronic stability control (skidding car symbol). I limped into a parking lot, shut it off and restarted and all seems well for the moment.

I've driven this thing to work about 6 times so far and taken a few short and mild off road trails. I put 35's on it and used a proCal to adjust the tire size and disable the tire pressure sensors. I changed the oil.

Making time to go to the dealer with this is a pain. Is there anything that could be going on that doesn't involve bad or improperly installed parts?

arasco85

I would demand a different one. That is rediculous or maybe flash it?

ronjenx

It may be related to the programming you did, if it something didn't get applied correctly.

Can you go back to the original tires, and put the programming back to stock?


Here is some info for the code you have:

P0507-IDLE SPEED PERFORMANCE HIGHER THAN EXCEPTED
Theory of Operation
The objective of the Idle Speed Rationality is to monitor the ability to achieve and maintain a steady idle condition. The monitor will judge the functionality of the idle speed control system by monitoring RPM during idle. If RPM does not come within a calibrated deadband of target idle speed, a timer is started. If the timer reaches its maximum threshold without any sign of the RPM trending towards control, a soft failure is generated.
When Monitored:
With the engine idling in drive, the brake applied, engine run time above a minimum calibrated value, and no VSS, MAF/MAP, ECT, TPS, ETC, CKP Sensor, fuel system, or injector DTCs present.
Set Condition:
Engine speed is 200 RPM or more above target idle speed for 30 seconds. Two Trip Fault. Three good trips to turn off the MIL.



Possible Causes

AIR INDUCTION SYSTEM LEAKS

PCV SYSTEM LEAKS

ENGINE VACUUM LEAKS

THROTTLE BODY

POWERTRAIN CONTROL MODULE (PCM)



U1412-IMPLAUSIBLE VEHICLE SPEED SIGNAL RECEIVED

Theory of Operation
The ABS Module sends vehicle speed information over the CAN C Bus circuit to the PCM.

When Monitored:
Ignition on.
Set Condition:
The PCM gets an implausible signal over the CAN C circuit from the ABS Module. The circuit is continuously monitored. One Trip fault.



Possible Causes

CAN C BUS CIRCUIT SHORTED

CAN C BUS CIRCUIT OPEN

ABS MODULE

POWERTRAIN CONTROL MODULE (PCM)

Mastiff

Yeah, I could just restore the system to factory with the procal. Speedo would be incorrect and tire pressure light would come on. I'll try that if it acts up again and see if it fixes the problem.

Maybe this happened because I removed the front air dam!

ronjenx

I was wondering if you should put the original tires on, too, if you still have them on the original wheels so it won't cost anything to try it.

JK in MX

any update??? I got a U1412 this weekend, from nothing... Jeep rides ok, but I am concerned...

Mastiff

It just never came back. I have about 4k on it now. I did fix an issue where the track bar drop bracket was not installed correctly (left out the bolt that requires drilling), so that could explain the stability thing possibly. I have no explanation for the engine specific codes. I may have redone the procal thing, I honestly just can't remember.