PASM Failure 987.1S

[andrew.nugent]

Hi All,

As a quick intro, I bought my first 987 S in late 2025. It's a 2005 Boxster S, with 120k on the clock. What a car!

Not long after having the car the PASM failure light appeared, I ran a diagnostic test and the result was a failure on the driver side front shock, So I fitted new full shock and coil assemblies on both front ends, (which was due anyway) as i believe it was the route of the problem, but the fault persisted. I fitted Bilstein PASM shocks specific to this car. Both rear suspension assemblies were replaced about 2 years ago, and the front coil springs were replaced about a year ago, before I bought it.

The faults, these came up on the reader under the 'Level control/PASM' section:

-Passive/sporadic shock absorber valve (codes: 0D,0E,0F,0C) for all 4 corners.

- Steering electronics control unit fault (drive) (code: C203) which sometimes displays.

I've checked the battery condition which is healthy. No sign of blown fuses. Shock body wiring connections and cables all sees ok. I've replaced both front ABS/speed sensors to try and diagnose the problem, as I learnt this could be problem.

What i am yet to check are the PASM module and wheel accelerometer sensors, they are on my list of places to check or replace. The car hasn't been in for wheel realigned since I did the work but it is booked in for one in 2 weeks. In the meantime, I'm working my way through potential causes.

Could anyone shine a light on this issue or has anyone overcome this problem before?

Any help and advice would be massively appreciated, I'm itching to get it back and on the road!

Thanks in advance,

Andy

 

[Motorhead]

Hi Andy,

The PASM module will speak to other modules like the PSM and DME which have inputs from wheel speed, steering angle and lateral and longitudinal body acceleration sensors, etc., so maybe that’s why you’re getting the steering fault message, but the one about damper valves sounds as though it could be PASM module related because it refers to all 4 dampers?

From experience on my 987.2 CS, when PASM failed it resorted to a teeth-rattling Sport mode, along with a permanently displayed error message. Is that what you’re getting?

You say that you replaced the front dampers with Bilstein units, but were the rears replaced with the same or genuine Porsche parts? I was wondering if there could be a compatibility issue, but if the problem has only just occurred I assume that can be ruled-out.

Not much help I’m afraid, but I would agree that you should check-out the PASM module and the front and rear accelerometers at the damper-to-body locations, although I guess that’s going to be restricted to the connections unless you want to get into potentially expensive part-swapping. Also make sure that the ride-height sensors are serviceable since they’re vulnerable to corrosion on a high mileage car like yours.

Jeff