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PRND all lit

Chrali

Well-known member
Joined
25 Apr 2018
Messages
53
As promised in my intro post I got my iCarsoft POR II today and checked for DTCs. I have the following:-

DME reported DTC1314
Tiptronic and P2281 (Boost leak between MAF and TB)

These seem pretty common and related, but why would a boost leak concern the transmission?

I'll check the transmission connectors and wiring for oil if the rain holds off this weekend.
 
Transmission uses the load signal which is generated by the maf .

Do you have any actual running faults or eml light on ?

Ive got a weird hunch this is to do with the pipe by the o/s/f air filter / coolant bottle .. might not be but it rings a bell .. there is a pump there and the pipe going to it is known to crack with age .. i need to look into it more when i have time .. the weekend me thinks .
 
Interesting about the trans using maf, never heard of that before.
Gearbox works ok in auto, or in tiptronic using the steering wheel buttons, but not responding to tiptronic on the gearshift. The PRNDL lights take about 20 minutes to all light up. No eml. From what I've found, it can also be the corrugated pipe across the front of the engine, or the y intake etc. I'll take a better look at the weekend as well, but at least I'm a bit more reassured that its nothing terminal. Thanks for the suggestion of where to look.
 
Well other codes are now showing after todays drive, the full repertoire.

P2281 Air leak MAF to TB
P2187 System at idle bank 1
P0011 Camshaft position timing over advanced or system performance bank1
P2189 System at idle bank 2

Better get this to a specialist as I have no vacuum testing kit and cannot see anything obvious, but engine seems noisier and I don't want to cause damage. I'll see if I can attach a sound clip / video tomorrow.

To be honest I'm beginning to feel some regret and I've had all manner of 10+ year old big old luxo barges.
 
Most of the codes are related to an air leak ..

A smoke test is needed first off i think .

The camshaft one is unusual though .. cam solinoid or even old / wrong type of engine oil could be a factor there .

EDIT...

Just a thought but on the Y piece going onto the throttle body there is a pipe in the middle of it .. make sure thats pully pushed home .
 
deMort I fully agree! I've booked it in with a local(ish) specialist who seems to have good reviews. It's also getting the transmission fluid and filter changed, as well as the engine oil. The Y piece is on just fine.

I intend to do these myself in future but it won't hurt to have a receipt for this in the paperwork. The transmission fluid and filter change seems pricey (I had my 760's valve body removed, seals replaced, and OEM fluid and filter for the same cost) , he quoted £540 for genuine Porsche fluid :eek: I've chosen the OE equivalent !
 
Took the car to the specialist this week. They had the car for an extra day as one of the engine drain plugs was damaged and they needed to get another (before filling with 5w 40). He said he'd seen worse transmission fluid but that it was over 1.5 litres low. He also said someones been in the front of the car before as there is some new pipework, and that'd he'd given it a quick look over and there are no leaks and looks like a good one .... phew !

They gave me list of codes from PIWIS but didnt go really into the DTCs this time, they said just drive it and see how it goes and they'll work with me to get it sorted. I'm okay with an iterative approach, as long as the driveability issues are resolved.

The garage is down many miles of country lane and the drive back was the first drive that didn't disappoint. Firstly it used to stay in 2nd gear for several minutes feeling very unnatural, now it goes through the gears much quicker. Secondly, the transmission does not drop into limp home fall safe with the flashing lights and rough down shifts. Thirdly the camshaft position warning which appeared to trigger the engine management light didn't return either.

Here are the codes, but nothing seems terrible.

P2281 unknown dtc?
P2187 lean at idle bank 1
P2189 lean at idle bank 2
1314 DME Tipronic
1314 DME PSM
1299 gateway AC
1299 gateway instruments
459 PCM2
0532 power supply engine
0459 PCM2
0907 load management on electrical system
2086 corn sensitive headlight left
1520 rain sensor/light sensor
1467 -> 1440 wheel electronics
1477 system off

So today is a good day so far.
 
Double post ... deleted
 
Its a sensible approach to finding a problem if its not a permanent fault .

Fault code P2281 air leak between maf and throttle ..

Unknown is just that they are useing an old tester or a non Porsche one .

This tallys in with the lean at idle faults.

Other faults are flat battery related or a fault with a cornering light and a rain sensor fault.

load management is a common fault .. car has been left with ignition on and not running for too long .. 5 mins is all it takes sometimes for this fault .

Still seem to have an air leak fault as i thought you had cleared those codes ?
 
Spot on with the load management code, i had the ignition on when i had the carsoft device attached until the car warned me about the battery.

Most of the gateway errors are failing to communicate with the PCM, which is not surprising as its not there, having been replaced with a Sony headunit.

The wheel electronics are due to the TMPS sensors I had removed as the batteries had expired and there is a separate code for that fact the TMPS is deactivated.

Left cornering lamp was known as I get a message on the dash.

Rain sensor / light sensor is ;in retrospect, no surprise as the head lights are on even in auto.

The garage made a point of saying they use genuine Porsche diagnostics.

I did clear the codes using the icarsoft, but no investigation work has been carried out yet, so these faults are current. I've ordered some MAF cleaner and will give them a clean and put on some new air filters whilst I'm there and see if anything looks amiss whilst its apart.
 
Think I've found one of reasons for the PRND lit fault.

I've been searching for reasons why the transmission drops to limp home after 10+ minutes. My overall plan is to replace what are the common low cost failures, so I haven't wasted my time taking the Cayenne to another county just to get Porsche to investigate something I could have done myself.

I definitely seem to have unmetered air what with the P2281, but then realised the other day that I could go up and down the gears using the buttons on the steering wheel, but not when using the gearshift lever and the other day the Cayenne started off in 1st gear which seemed very odd.

So whilst I was enjoying my corning lights I carried out a simple test. With the Cayenne idling I could swap between gears 1 and 2 using the steering wheel buttons. When using the gearshift lever in tiptronic mode I could select gear 1, but not gear 2. I've also noticed that when you pull the gearshift to select gear 1 it does select the gear, but if you pull it a little more it makes a click sound; like a torque wrench makes when the torque setting has been reached.

The failure to manually select gears seems to be exactly the scenario detailed on an article I found on pelican.com https://www.pelicanparts.com/techar...ement/11-BODY-Shift_Gate_Trim_Replacement.htm

The shift gate cover doesn't seem torn, but something in the mechanism feels like its causing an obstruction and does seem to also be an issue on the Touareg forums, where some people have reported fixing this resolving their PRND lit issue, as the sensors on that cover tell the computer what gear the vehicle is in.

So I think the next job is to replace that shift gate cover part number 95555226500.
 
Ok .. my thoughts ..

It drops into limp mode but so far there have been NO tiptronic fault codes so the box thinks everthing is fine .

The DME however doesnt and has a few problems .. airflow / maf being the main one .

Tiptronics need to know the load on the engine and airflow volume is a basic requirement of that so im leaning towards an engine fault is causeing the tip to go into limp mode .

A tip fault Will generate a fault code .

I take it if you drive the car only in auto it still goes into limp mode .. or does this only happen when you use manual ?

If the car doesnt know the gear position then that will be a problem , common on 996/986 tips .. the cable linkage seizes for the gear shift.

If you have a similar issue on the gear lever houseing then in theroy it would do the same .. you will get a fault code on the sports cars but im not sure on the Cayennes .. never had this fault before im afraid .

Its worth stripping and having a look thats for sure .

Its a lot easier when i have the car to look at i can tell you :p
 
Yes the fault happens in automatic as well and there are no specific transmission codes.

The shift cover replacement 'looks' straight forward, I guess we'll see. It definitely needs replacing though.

Now as for air leaks; I spent a few hours checking the engine bay, removing the engine beauty covers, checking for obvious splits and so on, including the intake Y. I couldn't find any damaged pipework.

Neither of the plastic pins that secure the Y piece to the throttle body had the little locking stub on them, but I guess that's not enough to throw a code as I assume the pins being pushed hope is enough to lock the Y piece.

The rubber hose connections shows some oil residue as did one side of the Y so after giving the throttle butterfly valve, pipework and sensors a clean, I just buttoned up everything very securely.

Now my test route is about an hour round trip and the transmission usually faults on the outbound drive, today it didn't fault on this trip at all.

Later on we went for a drive and yup it faulted at some point. I'll replace the shift cover and may as well replace the Y piece and its locking pins, but then its down to try and find someone who sees a lot of these as I don't think my local(ish) specialist is right for this.
 

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Shift cover changed out.

I changed out the transmission shift cover tonight. Broke a couple of tangs on the white plastic surround when removing the black plastic cover with the circuit board, but everything seemed to snap back secure enough and went back together with no problems.

The old cover wasn't torn but the rigid plastic rectangle that the gear lever pokes through had come adrift and that was enough for it to prevent tiptronic gear selection and that odd clicking sensation when pulling the when using the full travel of the lever in tiptronic mode.

A test drive shows that the tiptronic function has been fully restored and can now go up and down all of the gears fine with a smooth action. So I'll call that a win.

Also since I remove and cleaned checked and tightened the hoses I no longer have the P2187 System at idle bank 1 or P2189 System at idle bank 2 codes.

The P0011 Camshaft position timing over advanced or system performance bank1 hasn't reappeared again, but I haven't hit red line when it happened before, although I've been pretty close.

So right now the only codes I have are the P2281 MAF to TB leak and Tiptronic P1314
 

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