I have a 2006 LR3 HSE that had the sunroof drains leak into the driver and passenger floors, which started giving me the HDC & Transmission fault warnings and the DSC light, amber "BRAKE" light, and amber EAS light. After fixing the drains, I repaired a couple of splices in the door jambs but I still have these issues. When I scan it I get the following:

U2023-86 (27) Custom error code
U1A35-4A (2F) Unknown trouble code
U0402-94 (27) Invalid Data Received From Transmission Control Module : Unexpected Operation
U0416-94 (27) Invalid Data Received From Vehicle Dynamics Control Module : Unexpected Operation
U0403-94 (26) Invalid Data Received From Transfer Case Control Module : Unexpected Operation
U0421-94 (27) Invalid Data Received From Ride Level Control Module : Unexpected Operation
U0416-86 (A7) Invalid Data Received From Vehicle Dynamics Control Module : Signal Invalid

The vehicle starts and runs fine, it just won't go over like 40mph. I've read a ton of threads and checked/did the things that worked for others, but no luck for me:

-replaced brake switch and bulbs with factory parts/bulbs
-replaced battery
-hard reset, codes come right back
-checked TCCM, no obvious damage
-checked and repaired factory wire splices in door jamb
-checked harness & connections at shifter, under center console
-checked all fuses, FLs, and relays

Any ideas?


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Thats a mess. First thought is CJB. Were these codes there before the fix too? Did you disconnect the CJB connection at any point?

 

Yes, they were there before the fix. I did pull the CJB to fix the sunroof drain but the codes were the same before and after I pulled/reinstalled it. Is there a way to test the CJB? It looks good, no corrosion or anything on the connectors. Thanks.

 

Then it looks like a bad module is causing a CAN bus issue. CAN bus is in a loop. Maybe the Vehicle Dynamics Control Module is the culprit given it has the slightly different code. Now you can bypass a module on CAN bus using a resistor if you look up how. That could help rule things out maybe. Beyond that, someone else will have to chime in cause I am not sure what else it would be besides some sorta communications issue.

 

Ok, I got an IIDTool so now I know what modules are throwing errors. The TCCM error caught my interest. Could it be that someone troubleshooting this error before me swapped the TCCM without programming it? I'm assuming if you replace the module it needs to be programmed, is that correct?

Also need to check the oil temp sensor and wiring back to ECU. Engine runs fine, coolant temps stay in normal range. I suppose a short in that wiring could affect the Bus signal.

I'm fairly certain it isn't a simple short in the usual places. I've taken out the door sills, seats, and carpet to check wiring. Also checked the usual suspects in the engine compartment and the connectors in the rear wheel well area.

 

TCCM needs programming but have heard that on some vehicles it didn't and just worked once installed.

 

I had a similar issue with a broken wire to the oil temp sending unit. I'll have to check to see what code it threw. The engine would start and run just fine, but the vehicle speed was limited. As I understand, the oil temp is a backup to the coolant temp loop. If it sends the wrong response to the ecu, it'll put the vehicle into "limp" mode. I've found that even though you'll see numerous faults with controls you need to look at the data to diagnose what may be triggering faults downstream, which show up as the invalid data codes you see. Look at the engine oil temperature sensor circuit "high input"... that's going to trigger faults as the system tries to protect the vehicle, hence the modules involved are not operating as they normally would now that they are in limp mode. At least that's how I understand it to be...

 

Removed & tested tested the oil temp sensor, it seems to be working (resistance decreases as heat is applied). Must be in the wiring. Does anyone have an ECU pinout diagram? The one in the manual I have does not match my 2006 4.4L.

 

Here

 

Thanks DakotaTraveler! I had no continuity @ the ECM on the black/green oil temp sensor wire. Traced it from the sensor and found a break in the wire. Once I fixed it, all the other faults went away. So add that to the list of things that can cause the ESC/trans/HDC/BRAKE fault.