ABS light on & Tiptronic won't engage Manual Mode

[dbookman]

I have a 99 996 C2. My car has been sitting for several weeks and when I took it out for a drive today the ABS light stayed on and the Tiptronic would not engage manual mode. Does anyone have any ideas as to how to go about troubleshooting this? I recently changed the ignition switch, but I imagine that that shouldn't have anything to do with it. Fuses look o'kay. I'm stumped!

Dave

[Loren]

Read and write down the faults.

Reset the faults and see if they come back.

If they do, report the fault code(s) here.

[dbookman]

Ok; I've finally got the faults:

DME - #169 IACV

TIP - #55 Speed Signal (FR)

ABS - #4200 Speed Sensor, Front Right

It seems like the right front speed sensor needs to be replaced. Would you agree? If so, do we have a procedure for this I can search for on the site?

Thanks,

Dave

[Loren]

Porsche fault 169 = P1551 Idle Air Control Valve Closing Coil - Open Circuit

P1552 Idle Air Control Valve Closing Coil - Below Lower Limit

P1553 Idle Air Control Valve Closing Coil - Above Upper Limit

Potential causes:

- Break in wiring.

- lAC valve faulty.

- DME control module faulty.

I would remove the Idle Control Valve inspect and clean it - it should move freely.

If it is really gummed up or does not react to 12 volts then it needs to be replaced.

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Tip fault 55 = P1710 Speed signal, front right -. signal implausible

Potential causes:

- ABS control unit

- Tiptronic control module

- Wiring

ABS fault 4200 Front right speed sensor wire

Potential cause:

Front right speed sensor, open circuit, short to ground/short to B+

In this case it looks like your right front ABS speed (wheel) sensor is either disconnected or bad.

[dbookman]

Thanks. I will give these recommendations a try.

[dbookman]

Update: According to my mechanic, the speed sensor and wiring check out okay. He says the electronic portion of the ABS control module is the likely culprit. I've found some used modules at Oklahoma Foreign that might work, and I'd also like to find out if you may know of any places that rebuild 996 ABS modules?