01 VPD SC

I'm going down the highway at 65 and I get the amber and red light. ASC/TRAC error and there was a second error which I don't recall may have said limp mode or something...

I pull over to the shoulder and my max speed is ~5mph. Accelerator pedal is pretty useless. Tried restarting about 5 times no luck (car restarts but still in limp mode), let it sit 10 mins and it restarted w/ no problems.

I'm familiar with ASC issues (I re soldered the board), TPS sensor (I replaced the entire assembly a number of year$$ back) and also familiar with the wheel speed sensors (I haven't done the cleaning) also familiar with low battery issues (I put the car on charge when I got home and it was not drained). The reason I'm writing this is that I'm familiar with some of the basic items that could cause this.

The problem I'm having is that when I pull the codes from OBDII as well as using my Autoenginuity code reader (jag specific codes) I don't get any codes that would indicate that the car ever had a problem. I will list the codes when I get home but they were for the alarm system, dash cluster and rear drivers side door.

So my real question is why no codes? Should be there codes after limp mode?

I want to know what to go after ASC, TPS, Wheel speed, Bat? I was hoping the codes would at least get me pointed in the right direction... but I got nothing.

Thoughts?

 

Here are the codes that I did pull

P1260 - Theft immobilize
U1135 - Driver Rear Door Missing Data
U1261 - Instrument Cluster circuit failure
P1111 - EUC check complete

I'm struggling to see how any of these codes would cause limp mode.

Thoughts?

 

Hi dneider,

You can ignore the P1111 code which just means the last system check was successful.

One of the first questions to ask when LHM occurs is whether the battery is healthy. Just because it wasn't drained doesn't mean it's as healthy as a Jag requires. It might be worth having it load tested.

The ABS/TRAC error seems like a possible clue, since the Transmission Control Module (TCM) receives its vehicle speed signals from the front left and right wheel speed sensors via the ABS/Traction Control Control Module. It might be worth checking the wheel speed sensors.

If you don't find any obvious issues with the sensors, the next question that comes to mind is the transmission fluid level. Slippage due to low fluid would probably trigger a DTC, but assuming the fluid level is correct is risky. While you're checking the fluid, it would be worth cleaning the electrical connector on the transmission with zero-residue electrical contact cleaner spray, and also clean the electrical connector at the Throttle Position Sensor (TPS).

U1261 indicates a Serial Communications Protocol (SCP) negative circuit fault in the Instrument Cluster circuit, which I don't think can be related to LHM since I believe the transmission-related communications are via the Controller Area Network (CAN). However, the IC does communicate with the Transmission Control Module (TCM), so I don't know if you can rule out an IC circuit problem from possibly being related to LHM.

The U1135 code means the ignition switch position status was not obtained, affecting the Passenger Door Control Module, Passenger Seat Control Module, or the Security and Locking Control Module. I agree that seems unlikely to be related to LHM.

Hopefully another member will have some better ideas.

Cheers,

Don

 

Could even be an air leak such that it had trouble getting fuelling right.

Check fuel trims...

Most codes are 2-trip so a single time would at most show up as a pending code (which some tools don't report).

 

Good call on checking trans fluid, I'll give that a shot. Haven't done it in a while. I have a dipstick, but need to look up what temp the fluid is supposed to be at when checking.