Hi all,


I took my 2008 CTT out to run some errands this morning. I started it fine and drove across town. Parked for maybe five minutes at my first destination and upon re-entering the car was greeted with the following codes upon turning the key:

1. PSM failure
2. Chassis System Faulty
3. Headlamp System Faulty
4. Oil Level Monitoring Failure
5. Oil Pressure Monitory Failure

PSM Failure (with light symbol below)

Chassis Failure

Oil failure

When I go to start the car, I get an error suggestion "Press brake pedal" despite the fact the brake pedal is pressed. The steering wheel also doesn't unlock. I have since worked with my mechanic who graciously was texting me on a Sunday to work through the following:

1. Headlights, Chassis level control continue to work despite faults.
2. Battery voltage was at 11.9 VDC, which is low. I swapped with a new battery (12.5 VDC), nothing new happened. My original battery appears to be < 12 months old and is an AGM
3. Fuses 7 & 8 in the driver side engine panel all seem fine (continuity exists). Fuse 41 in the door panel seems fine
4. There is no clicking or "slow turns" of the engine, the ignition circuit isn't completing
5. Brake lights respond to brake pedal press
6. Inspected the 433 relays in slot 20 in driver side panel (starter relay) and the relay under the driver's seat (ignition lock). I have two on order for tomorrow, as the parts shop won't charge me until I pick them up.
   1. The starter one had 0 ohms resistance on NO circuit (30->D), the one under the seat had 2 ohms resistance that would cyclically spike to like... 100 ohms. Not sure if that was measurement error on my part or the relay being faulty.
   2. The coil resistance (85->86) was 77.5 Ohm on the starter relay and 74.7 Ohm on the under seat relay.
   3. Neither coil had continuity across the NC circuit (30->87)

Is there anything else I should try before giving up on fixing this and getting it towed to my mechanic? I will be inspecting the harnessing tomorrow under the seat for water ingress and checking voltage at the starter. We had a pretty good snow here so that seems possible, but given it started this morning I'm super confused. My Durametric scanner arrives Wednesday and unfortunately the car is not in a place I can store it until then so I am facing at least one tow job.


Recent service:

• 11/17 - replaced the cylinders 4-8 PCV valve (107.5K miles)
• 10/19 - replaced the drivers side turbo & axel. Complete fluid swap on coolant, oil, power steering, etc. (106K miles)

 

Your battery is done. When you get multiple messages from unrelated subsystems that's usually the culprit. If not that, have you driven the car through a lot of rain or water lately where the spliced wire bundles on the floor may have become corroded from water.

 

Yeah, sleeping on it I'm fairly sure something's up with the harnessing. Given what others have seen with this type of problem, I'm hoping that letting it sit overnight will at least let me get it started so I can drive it home.

 

because this a weak point with this car….

is there a way to prevent problems like this?
is there a strategy/ trick to open up the carpet without damage?

thank you

 

Prevention is fine by keeping all the body and co drains clear so water drains easily.

From what I've read, you just pull the threshold plate up or the carpet out from under the edge of it so you can see if the foam padding is wet.

 

Thank you

 

SOLVED!

I gave up and had the vehicle towed to my mechanic (Berg Performance for those in greater Denver area). While it took a bit of discovery time, it was a relatively simple harnessing issue. The ECU power supply harness had come loose from the junction in the engine bay, resulting in not enough power going to the ECU and throwing all the codes I was receiving.

Car started up and is working fine again.

For those who might experience a similar problem, the harness connection is an eyelet on an M8 stud located near the posts used to jump the car under the battery cowl. I'd be mad, but I was never gonna find that issue on my own at the time.


Loose and melted terminal