Joec500

After 90,000 miles I FINALLY got my first check engine light. The car went into limp mode and PSM went crazy. I then reset the car and everything was fine, except for the CEL. I went home and connected my PIWIS 2 and pulled the code P2101. - Throttle Valve Adjustment Unit - Position Deviation.

From what I have seen in the Porsche Trouble Shooting it could be a short or corroded connections at the ECU. The car seems to be running perfect now that I cleared the codes and drove hard.

In the mean time I bought a new throttle body ($90 for a bosch unit brand new) and the gasket. Since the part was relatively inexpensive I thought I would have it on hand. I will take off the bumper this weekend to inspect the ECU connecter, maybe de-oxit it and replace the throttle body (probably have to recalibrate with my PIWIS as well).

Has anyone else here seen this issue?

991.1 C2S Manual and it happened on hard deccel after downshift and after I just filled my tank.

CSK 911 C4S

Where did you find it for $90?

I was looking at a picture and I take that the throttle position sensor is built into the throttle body itself.

I'm seeing it at $233 so $90 is pretty good.

Joec500

I cross referenced this from FCP Euro

https://www.fcpeuro.com/products/por...vD_BwE#fitment

with this part on ebay.

https://www.ebay.com/itm/303861121370

Both are interchangeable with Bosch

0280750473

Joec500

UPDATE, I received this TB today, quality appears really high, but it's a made in china knockoff, I will return it. I ended up getting a real Bosch one at Autozone for $150 shipped to my house with the SEPT15 promo code for 15% off. Not gonna take chances over 60 bucks. Also I believe the throttle position sensor just clips onto the Throttle body so it's a separate component. Also the this Bosch parts seems to have a lifetime warranty as well.

jaysc

Solid decision. Best of luck with the job!

barncobob

no to Chinee counterfeits,,,,would you buy a Chinese PDK?

asellus

Yes, if only out of morbid curiosity.

koala

While you're in there, is it worth replacing the throttle position sensor?

For the past year or so I've been in the habit of resetting the throttle position sensor each time I drive the car as it really seems to help get rid of the jerkiness / engine stumble symptoms.

Joec500

how do you reset the throttle position sensor? I will look into that too thanks for the heads up!

Also I don't really mind taking off the bumper, I can do it in less than 20 mins now

Joec500

For anything mechanical DEF NOT, some cosmetic things like key covers etc, I am OK with. I didn't realize it was a counterfeit until it arrived.

asellus

Turn the ignition on and don't start the engine for 30 seconds. Car has to be in ambient temps. It resets the adaptations for the throttle plate, which is something you should do when you replace it. The adaptations set back up pretty much immediately, so repeatedly doing this shouldn't have any actual effect unless your TPS, throttle plate, or throttle actuator is failing.

Unless we're talking about resetting the car "learning" how you drive, which is more a transmission thing, and is also a minutes-long tool assisted reset procedure.

koala

My evidence is purely anecdotal obviously, but I find that reset procedure transformative on 9 out of 10 drives. The odd time, it doesn't seem to help at all. But when it does, there is no stumble, no jerk, just silky smooth response at any engine speed.

asellus, I'll try the way you describe it. I've been turning the ignition on, leaving it for 60 secs, then I turn the key back to off, and then I fire up the car.

Joec500

yah I have a manual, so transmission adjustments are done on the fly

Thank! I do have jerky acceleration at low speeds some times.

asellus

Errr, I might be misremembering the procedure. Thought it was 30 in ambient temps, no need to cycle the ignition off, so I looked it up and here are the preconditions for the non-deletion overwrite of throttle valve adaptations:

- Engine off and ignition on for > 30 seconds
- Accelerator pedal not pressed
- Vehicle is stationary
- Power supply for throttle valve adjusting unit is OK
- Coolant temperature 5 °C... 100 °C
- Intake air temperature 5 °C... 30 °C

The FSM clearly states that this procedure, either done via the "turn on the ignition and wait" or via the PIWIS, is ONLY necessary after any of the following work is performed:
- Re-programming DME control unit
- Replacing DME control unit
- Replacing throttle valve

Which again is why I say this procedure is largely unnecessary to do repeatedly, and any real changes seen from doing this often likely indicates a failing component.

Further, if you attempt to do this and the conditions are not met, it will queue it up to automatically do it next time the ambient temperatures are met regardless of waiting 30 seconds. In this case, the engine will not start until the calibration is complete, which takes just a couple seconds, per the FSM.

If you wish to look this up within the FSM, it is under the heading:
WM 2X00IN IMPORTANT INFORMATION ON ADAPTING THE DME CONTROL UNIT > OVERWRITING ADAPTATION VALUES (WITHOUT DELETION) > THROTTLE VALVE

koala

Thank you, that's most interesting! I am convinced my throttle position sensor is faulty in some way then. I might just replace it for the hell of it. Does it need piwis or will the new sensor just "work?'

Sorry to sidestep/hijack your thread, Joe!