Got the check engine light, then the following codes:

6. Idle Speed faulty (how do I adjust this? what is the correct Idle speed?

9. Intake air temp sensor. Open or short ( should I just replace the sensor?)

17. Data Exchange fault between individual control module. ( don't even know where to start on this one?)

26. Upshift delay switchover valve, circuit open or short. (not even sure where this is located to check it out)

Any help would be greatly appreciated.

Thanks

That's a strange combination. I would clear them all and see what comes back. Eratic fault codes can be a sign of a bad wiring harness. Does the car run OK?

I'm not sure how to clear the codes?

Are you supposed to hold the button in for seven seconds after the every code individually? or after the entire sequence of codes has completed?

I just had the wiring harness replaced about 7 months ago along with a complete valave job. I guess its possible that the harness is defective, but the errors just started this week?

Thanks

I'm not sure - try it both ways. I try to hold it down for a count of 10 to make sure. Probably not the wiring harness then. I still think your next step is to clear the codes and make it do it again - assuming the car is running OK.

Are you supposed to hold the button in for seven seconds after the every code individually? or after the entire sequence of codes has completed?

. . . by bringing up each fault and within 10 secs, hold the button down for 8 - 9 secs for each fault.

6. Idle Speed faulty <-- no adjustment for this!

9. Intake air temp sensor. Open or short. <-- is it connected? Many times the connector is left off when working on the car.

17. Data Exchange fault between individual control module. <-- #6 and this fault MAY be the start of a bad ETA (my page, MENU#24).

26. Upshift delay switchover valve, circuit open or short. <--- maybe a bad vacuum line to the transmission.

__________________
Regards . . . . JimF
-------------------
'94 S500 Cpe

Visit my Mercedes Web Page

Some of this could actually be left over from the bad wiring harness - if the codes weren't cleared when the new harness was installed. Not everything causes the CE light to come on.

Ok, I reset the codes and they all went away. Just one LED blink now, no fault. Hopefully it stays that way. I just had the car smogged and it passed so I guess those codes must have been incorrect because if I did have that 26 upshift problem the car would have failed...

Thanks to everyone for all the usefull advice.