Diagnostics code help please 996 Turbo S

[getitupya]

Hi All,

I am getting various intermittent faults occurring on my 996 Turbo S, starting with the old favorite;

- PASM/ABS (this used to reset as soon as engine warmed up, but now stays on)

Then not so often (happened 4 times in all)

- the TIP gearbox defaults and sticks in 3rd (if you stop and switch ignition off, it clears)

and a couple of other randoms

- Spoiler not activated (it had)

- CD changer not located.


Living over 2 hours from any specialist or main dealer I took the car to a local "diagnostics center" and was left with the following when they reset the codes on the initial download and I ran the car for a short period.

Code 1 -
22 CAN: rear right wheel rpm from PSM implausible

Code 2 -
51 Transmission slips or gear implausible

Identification:
Diagnostics software number - 0102
Porsche part number: 9966181800

I am a bit confused as the code 0102 is for the MAF I believe and the part number is showing as the tiptronic control unit??


What should be my course of action?? Would swapping the rear wheel rpm sensors over be a good starting point and see if the fault changes to left rear?

Worthy of note that the PSM/ABS fault existed before a flat battery where the other faults have only appeared since the flat battery.

Thanks in advance!!

 

[Richard_Hamilton]

I'm not sure those Tiptronic fault codes are accurate. I assume they didn't use a Porsche tester, in which case they will be generic codes, rather than Porsche-specific ones. However, they do give a clue as to what is going on.

The P0102 DME code is, as you say, a faulty MAF:

P0102
115 Mass air flow sensor "" below limit
Diagnosis conditions:
"¢ Engine running
"¢ Battery voltage greater than 8 V
Possible fault cause:
♦ Open circuit
♦ Short circuit to ground
♦ Mass air flow sensor faulty

A faulty MAF is not programmed to trigger the Check Engine light on a UK car, but it will trigger the PSM/ABS lights. The reason is because the DME and ABS/PSM controllers communicate via the CAN bus, and the DME is sending an implausible signal to the ABS/PSM module due to the faulty MAF readings. The Tiptronic unit is also communicating on the same CAN bus, so it too is getting implausible signals.

I would fit a new MAF.

The spoiler and CDC are not related to the MAF problem, and are individual faults which need dealing with individually.

 

[getitupya]

Thanks for the reply Richard, I will source a MAF and try that.

I guess the wheel speed sensor needs changed also, or is worth waiting until I have done the MAF?

cheers
Murdo

 

[Richard_Hamilton]

I would wait until you have done the MAF, which might be causing the other fault codes.

Like I said, the fault code you have for the speed sensor (22) isn't a Porsche code, so I would be wary about it being for the correct wheel.

 

[getitupya]

I have ordered a new MAF and will try that first,

thanks again for your help Richard.