Dash Transmission Display Gone Wild

[spooltime]

I'm wondering if anyone has seen this before. After maybe about 15 - 20 minutes of driving, my dash disply shows this for my transmission gear selection:

Weird that I'm parked, reversed, in drive and in neutral all at the same time! This happens whether I'm in auto shift mode or manual shift mode. The transmission seem to continue to operate normally in automatic mode when this happens.

Anyone have a clue before it goes to the dealer?

Edited April 17, 2013 by spooltime

[hahnmgh63]

It looks like the transmission is in limp mode. That is the sign on many of the newer transmissions that they have a fault. I'm not 100% sure on what the limp mode display is on the Cayenne but it usually entails the Drive letters or gear numbers going into a reverse highlight. Does it go away when you come to a stop? Or just when you restart the car? I would scan it or have it scanned right away, do you have Durametric?

[spooltime]

Thanks for the reply. It doesn't feel like it's in limp mode when this happens, but maybe I just can't tell the difference. It clears only when the engine is restarted, and it doesn't matter whether I'm driving in M mode or normal automatic mode.

I'm expecting to take delivery of my Durametric any day now and will scan the control units when it arrives. I'm hoping it's just a fault that can be cleared.

[hahnmgh63]

If it clears after a restart and then comes back it is probably a very repeatable fault and not intermittent which could mean many things. Bad TCU (Tranny Contol Unit), bad wiring, Stuck Solenoid, Tranny Temp sensor, many things. But Durametric should narrow the fault down but sometimes it can just give a genaric reading but it's a must to start with. There are a few people on the list here with some good Tranny know how so maybe one of them may pipe in, also try posting over on Rennlist when you read the fault.

[mcbit500]

On mine this was accompanied by harsher than usual auto shifts and was cured by replacement of the EGR valve.

[spooltime]

On mine this was accompanied by harsher than usual auto shifts and was cured by replacement of the EGR valve.

Do you have a part number for the EGR valve?

[RFM]

Will be difficult, i think there is no EGR valve in your V8 engine.

[darrinsmith]

I had this error once when I accidentally "activated" the transmission control unit when I was mucking around with some wiring installing my dension gateway.

Initially I crapped myself, but the error cleared on the next restart.

A durametric scan will definately help, my problem was that as the module was awake, the transmission was not and it was complaining that the transmission wasn't there.

Cleared the codes and never had a problem since.

But it's definately the car saying there's a problem.

If you post your error someone here will be able to help.

Cheers

DS

[wvicary]

You really need to have the fault codes or it's all a guessing game. The gearbox is having some sort of fault and also check the DME, ABS and instrument panel for fault code relating to the gearbox.

[spooltime]

My Durametric arrived in the mail Saturday, and I was able to survey the control units for fault codes using the latest version of Durametric's software. I need to preface this by saying that for that last three days, the display console hasn't done the "I'm in every setting mode" once. The only fault that came up was a P2329, air leak between MAF and throttle body, with a notation that the fault is not currently active and is not causing a DTC light. I then did the clear all fault codes routine with the Durametric.

On the first drive after clearing the control units, I have to say I honestly believe like it felt like a different vehicle. Throttle response was far more pronounced, gear shifting seemed more pleasing (not shifting up and down frequently seeming to hunt for a gear), and still no more crazy dash display. I'm going to continue to monitor this issue, and probably scan for fault codes on a weekly basis for awhile, but for the moment, it seems to have resolved itself. Very weird indeed.

[spooltime]

Well the transmission gear selection display did its thing again a few times the other day and I had a chance to pull fault codes today. The problem is definitely intermittent, since it will go days between having this odd display on the instrument cluster.

The DME has a P2329 code, which is indicated to be an air leak between the MAF and the throttle body. But the transmission controller was showing a "1314" error code, which I haven't been decipher or interpret. Anyone know what this is?

And finally, the vehicle electrical system was showing an error identified by the Durametric software only as part number "11". Again, I have no idea what this could mean.

All help and insight appreciated!

[Loren]

Fault code 1314/P0614/P0864DME control unit [ECM/TCM Incompatible I TCM Communication Circuit Range/Performance]

Possible causes of fault:

The Tiptronic control unit is coded in the DME control unit!DME control unit was replaced and coded incorrectly or was not coded (no or incorrect basic setting/adaptation)

- Engine type coded incorrectly (no or incorrect basic setting/adaptation)- Transmission type coded incorrectly (no or incorrect basic setting/adaptation)

- To localize the fault, read out the fault memory for the 'DME control unit' (Please read out fault memory)- No message from DME control unit on CAN drive (no signal/communication)

Sounds like the system needs a programming refresh (you will need a PIWIS and IPAS codes to do that).

[spooltime]

Thanks for that. Looks like a visit to the dealer is necessary.

[mcbit500]

Will be difficult, i think there is no EGR valve in your V8 engine.

Found the bill. Described by my Porsche specialist shop as the EGR valve it is valve on the opposite end of the hose from the Secondary Air Pump and described in PET only as Valve.

[clarksongli]

Will be difficult, i think there is no EGR valve in your V8 engine.

Found the bill. Described by my Porsche specialist shop as the EGR valve it is valve on the opposite end of the hose from the Secondary Air Pump and described in PET only as Valve.

EGR and SAI are two separate items.

EGR uses only gas pressure from the exhaust stream to recirculate back to the intake tract....dilutes the intake charge and improves emissions performance, specifically oxides of nitrogen.

SAI uses a pump to drive fresh air into the exhaust stream, especially during cold starts, to help reduce emissions by allowing excess fuel to be burned in the cat.

These would NOT be connected together as mentioned.....

[mcbit500]

Whatever the valve is on the other end of the hose from the secondary air pump is, changing it cured my transmission fault.

[spooltime]

described in PET only as Valve.

If you found the part in PET, can you share the part number?

[mcbit500]

Part no from PET 948 113 203 051. That was my problem but may not be yours.

[spooltime]

Thanks for the part number, but I couldn't get it to come up as a valid part number. I looked at the parts diagram for my vehicle, and I think you're referring to the secondary air injection shut-off valve. Since it's a $100 part, I'll be better off spending the $100 on labor at the dealer for a correct diagnosis and repair, but I'll suggest the valve as a potential issue to my service writer.

[spooltime]

So the CTTS is at the dealer and they'd never seen a dash do this before. The diagnosis now is that some sort of internal leak in the transmission case is causing fluid to wick up the harness to the TCU, which is located under the passenger seat, causing it to create some kind of short and trigger the errant display.

The upshot is that because the wiring harness is fluid-saturated, they're replacing the harness, the TCU, and since they're already in there, doing the filter and tranny fluid. And for good measure, the tech also discovered some sort of control valve for the turbos was limiting boost to about 50% of normal, so they're replacing that valve as well. I can only imagine what it's going to feel like when I have access to the full boost it's capable of. And knowing what gear it's in.

Edited May 10, 2013 by spooltime

[wvicary]

I have seen fluid ( gear oil,coolant, etc) be drawn up a harness and in rare cases into the control module.

[spooltime]

As previously noted, the dealer identified a transmission fluid saturated wiring harness leading up to the control unit. As a result, they replace two wiring harnesses between the transmission and the TCU. The repair necessitated dropping the tranmission oil pan, so I also paid for a transmission filter and fluid service. This repair seemed to have taken care of the problem initially. The transmission shifts were buttery smooth and the gear indicator display seemed to function correctly. But then driving down the interstate two days later, the lights lit up again . . . all four indicators just as shown in the original photo.

To make a long story short, the Cayenne went back to the dealer and spent the next four days there. They did end up re-flashing both the ECU and the TCU and for the past couple of days, have logged many, many miles and a tank of gas verifying the repair. It seems to be fixed now, and most likely was a glitch in the ECU coding. However, the other repairs were necessary, and I also take comfort in knowing the transmission also has been serviced with fresh fluid. I'll keep my fingers crossed and hope the issue is permanently resolved. BTW, the second four days it was in the shop were at no charge to me. I thought the dealer really stepped up to the plate on this one, and they've earned my repeat business as a result.

Edited June 12, 2013 by spooltime

[spooltime]

Another update.

The "display" came back, so it wasn't repaired after all of the time and money expended thus far. My Durametric again reported a "P2329" code, so I perused the OBDII Diagnostic manual for the Cayenne I recently acquired and shock - there is no valid DME 7.1.1 P2329 code. I contacted Durametric tech support and received a response acknowledging that a faulty formula used in the software was generating fault codes with a value of +48 for the expected fault codes in the upper range of expected fault codes from the DME 7.1.1. That's just frickin' great! You can't even rely on the accuracy of the fault code being reported by the Durametric software. They did say the next version of the software should resolve the problem. In the meantime, my advice is treat your Durametric fault codes with skepticism, they may not be the right codes - very disappointing considering what the Durametric cable costs.

So the correct fault code is in fact, P2281, which is a leak between the MAF sensor and the TB. This makes the new suspected culprit perhaps either the Y-plenum with a slight crack, or some other air leak along the way. The CTTS is back in the shop and they will be pressure testing using their smoke machine to track down the source of the leak. I'm hoping they do find the leak, because each time the display has gone whacko, the same fault code has been returned by the Durametric (after having previously been cleared). Somehow, it seems wrong that I am the one telling them how to find the problem, but if this fixes it, it'll all be good regardless.

[spooltime]

Final update - hopefully.

Armed with the diagnostic insight I provided them, the service tech at the dealership did supposedly locate a small leak in the air line coming off one of the turbos. He corrected the leak and once again, they claim it is repaired. So my CTTS ends up with new wiring harnesses and a new TCU it probably didn't need, the dealership ends up with a nice "wallet share" from me, and maybe, just maybe, I now have my CTTS fully sorted. It's running beautifully now, and to the dealership's credit once again, there was no charge for my third and hopefully final trip regarding this particular issue.

Now if only Durametric would fix their software so it actually yields correct and valid fault codes, we'd all be better served.

Edited June 13, 2013 by spooltime