Good morning Friends...

I took apart my dash the other day to begin replacing all lights in the center console. Nothing tough about it except me, the brute I am, needs to work a little more carefully than I am used to. Adjust, adapt and all that good #$&#*!

Putting things back together, were together, I accidently hit the Trac Off button, car running in park. The dash display went haywire!!! Trac unavailable, gear box fault, restricted performance, ABS light, low brake fluid and an audible noise (that I haven't rightly investigated yet) sounding like a pump from the area of the ABS module...

I have NO clue. To reset things,,,, I turned car off - which I knew would reset the button - to find that some of the faults/warnings remained... Drove for 100yds, turned car off again, restart, everything returns to normal...?

Obd fault codes attached.

I'm mostly looking at the "Power Train" codes. I've been living with the 1396 (long story having to do with VVT) since replacing the heads. 1111,,, living with. And the 02 sensor, comes and goes.

What's going on with this? Anyone have any experience with these kinds of problems?

 

Not sure why the P0420 but the others could have been something disturbed when you were replacing the items in the center console. You could clear codes and see if they return - could just be a fluke

http://www.jagrepair.com/images/Auto..._2001_OBD2.pdf

P1111 IS NOT a Fault!!!!! It's a Systems Readiness test - means all systems have completed their checks since last memory clear. This is a good thing

P0420 OBD II Catalyst efficiency below threshold A bank (1)
Engine at normal operating temperature; IAT > -8 °C (18 °F) Varied driving for 3 minutes; then, constant steady throttle 50 – 60 km/h (30 – 38 mph), 1100 – 1475 rpm > 25 seconds Surface elevation < 8,000 ft (2,438 m)
2NNone—HO2S disconnected HO2S to ECM wiring fault HO2S heater to ECM wiring fault HO2S heater failure Upstream HO2S failure Downstream HO2S failure Catalyst failure

P1638 OBD II CAN INST token message missing Ignition ON > 5 seconds1NNone (Engine speed and coolant temperature data missing at instrument pack)
EM83 -15 -16 -24 -25
CAN open circuit fault – INST to ECM CAN short circuit fault INST failure ECM failure

P1642 OBD II CAN circuit malfunction Ignition ON > 5 seconds11 [M]
When fault is detected, ECM: – Limits throttle to approximately 30% – Inhibits cruise control (All CAN data unavailable)
EM83 -15 -16 -24 -25
CAN short circuit fault Control module failure – check for additional flagged DTC(s) to locate control module source

 

Wow SK! That's a lot of information and I'm going to have to go thru it slowly...

Let me add this now or maybe I should start another thread? I have a feeling it might be connected but could be wrong - with this thing - I have been before.

Now,,, my alarm system will not ARM... I just went and made sure everything was buttoned up. Dropped and reclosed top, all windows and doors. Used key to drop top and reclosed. When I hit the ARM button on the FOB,,, I get the single hi pitched beep. When I push ANY button on the fob,,, a high pitched beep. No lock or unlocking of doors. No normal "chirp" either way...

When it rains. She runs and starts normally. No more indicators on the dash display... CraaaZZy...

 

One other question,,, and maybe I should clarify something.

I did the work on the console 5days ago. Put everything together, hit the button by accident, had the problem, "cleared it up" and drove 100+ miles... I did the work at a vacation home over the weekend.

This morning, while warming up the car, I hit the TRAC button again, sending the car into the freakout I described. Turned off car, drove it 100yds, turned it off, started it again. Back to normal (with stored codes)...

What is the relationship between the TRAC button, and all of this? In you all's experience...

 

JJJ, the description sounds so much like my dash on the day my alternator's low output pushed the battery charge into the red, I gotta ask can we eliminate battery voltage?

How hard would it be to get back into the switches you worked on? It seems so likely that the issue is there. Did you do any soldering by the trac off switch or its traces? Imagine if a solder splash landed on the circuit trace so that all's good until you push Trac Off sending normally isolated voltage into the wrong part of the circuit...

Since its directly tied to pushing that soft button I'd look for a mechanical in that part of the circuit for starters (by mechanical I mean solder splash, conductive debris, burned trace)

John

 

Here's the switch itself.

 

Thanks John!

No soldering. Replacing and identifying bulbs that need(ed) replacement. Everything went fine. I did some between button grime removal. Nothing out of the ordinary. "Buttoned" it back up and drove it 100 miles, into night and night drive lighting usage... No problems. Have driven it 10 times since then.

When I hit the button then,,, and this morning, haywire. I've never used the button before this.

-Audible pumping sound or engagement under the hood. Seems to be coming from the ABS control area on the LH engine compartment wall...
-ABS light in tachometer area ON.
-Gear box fault.
- Trac not Available
-Low brake fluid
-restricted performance
-THE WORKS

Turn off the car and restart,,, things basically go back to normal. "Restricted performance" will last... Then, drive it a little bit, turn off and restart. Back to normal. No RPerf...

I hope that clearing the codes has an effect on the alarm system. Nutts!

And,,,, I'll NEVER touch that button again, lol

Seriously though... I would like to know what this is all about.

 

And Oh yes... I am confident the alt and battery are fine... Confident.

 

Thanks for these! Looks like I'm going to have to dig into my XK8 electrical book (PDF)...

Unlike the 86 928 or the 90 XJS books,,, the xk8 book ALWAYS has me head scratching... So hard to read.

 

Whew, that's a good one. What yr is she?

Back when I had bad motor mounts I had a similar situation. All ok until car tried to maintain speed cc on, starting to go up hill. I'd lose the cruise control (cc), get restricted performance message and trac stability failure message. Would always reset with ignition cycle.

Turns out the engine movements were so big with failing mounts that it pulled the vaccum pipe off throttle. Car tried to maintain speed with the vaccum assist. Speed dropped, confused the car = errors.

Now this is different than your issue, but wanted to describe it to maybe spark a different perspective. This seems to be tied to the trac switch diagrams above don't point to much as far as causality goes. Darn Jay, wish you splashed some solder :-) this time.

Pushing the switch grounds the lead into the module. Could it be a bad module? Wonder if the module is close to your work.

John

 

Hi! Thanks for the attention and well wishes.

Yes, on the 2002 the switch/button is part of that pack of switches that contains rear and forward fog lights, heated seats L and R, hazards, TraC Control (of course) - and maybe one other...

Personally, it think this was a pre-existing problem, discovered at accidentally hitting the TRAC button,,, and then hitting it again today... Honestly, I have no idea where to begin.

In some code look ups (for the thrown codes I got this morning) there is reference to CAN information. To tell the truth,,, I don't know much at all about that set of systems... either

 

I have experienced some of these symptoms while I was investigating my own can bus issues. I had recently been working around the TCM and ECM in the engine bay. I think I had bumped into the TCM connector and caused a intermittent bad connection on that connector. I resolved the issue by unlocking that connector, fully removing it, and then reseating that connector. Do this with the negative battery cable removed and touching the positive battery cable to make sure that you are working with a fresh slate.

This is of course a hail mary type play and definitely not what you would be doing if you wanted to scientifically run through all of the options that could be causing you problems.

If you are truly interested in trying to troubleshoot this problem from point A to point B, I think there are a few of us on the forum that have had the misfortune to have a bit of experience working with the TCM and ABS modules and the can bus. I would definitely be willing to help, as everyone here is more than willing to help me.

EDIT:
I also can't help but wondering as to whether or not @Johnken is right in guessing that some solder got into a place that it shouldn't. The previous owner of my car decided to resolder the abs module themselves and had made a mess of the leads of my abs module. The traction control button that you are pressing is directly connected to the abs module and I am not aware that the abs module even reports the status of that button to any other module in the car using the can bus. So that switch just sets a state inside of the abs module and I would imagine any fault regarding that switches operation would be a physical problem or located inside of the abs module itself. The traction control switch is a momentary ground signal. The error messages that you were getting lead me to believe that you were having interference with the can bus system between the ECM and the INST gauge cluster. I know that the dashboard will display the gearbox fault message when the ECM isn't getting the can bus communications through the TCM connector. All of those modules losing connectivity to the ECM at the instant you pressing the button makes it seem like you have a short between that button and one of the can bus data wires possibly? But is it inside of the ABS module, or is it a physical short between wires in the wiring harness somewhere? Could it also be multiple problems happening at once and you are just reading all of the error codes after the fact.

 

Good Morning Mad and All...

Sorry for the short reply. Two reasons. 1. Porsche 928 rear end work today. Excited. 2. I don't know much about the system you all are trying to teach me about ie. The CAN systems or the ABS. Sad but true...

In working the other day there was no soldering. BUT 2 yrs ago that initial solder point inside of the ABS module did fry and was causing me all sorts of grief. According to the instructions provided by you wonderful people I cracked it open and soldered it up... One of my first soldering jobs ever. It might be possible that I crossed some connections in that operation...?

 

I don't know the internal layout of the traces inside the ABS module near those solder points. It certainly is possible.

Take the connector off the ABS module and you have access to test the integrity of the stability control button circuit.

Pin 14 in the ABS module connector is directly connected to that button. It is labelled as a momentary ground, so if you take your DVOM then it should be an open circuit until the button is pressed, and then should be a clean ground with the button depressed.


If all seems well with that sanity check on the button circuit then we can conclude that it is likely a problem inside of the ABS module. You could open it up and see if your solder crossed some circuits that shouldn't have been, or try to find another ABS module to test and replicate the issue with. Of course there could be an intermittent physical connection to another wire somewhere in the wiring harness and the only way to really eliminate this would be to visually inspect the wiring harness from point A to point B.


I am not certain if you are possibly doing damage to the modules on the can bus when you are experiencing this problem, maybe someone else could chime in that knows the over voltage protections in place in the modules on this car? These electronic modules are made quite poorly so my initial guess would be little to no protection against damage on these circuits.

 

+1 with Mad Hatter's suggestion.

John