Craig Bastian

G'day long tail short ending.

This is fall all high idle and surging when reversing.

My daily driver C200 m271 03 with high km's. My motor and gearbox started to play up about 4 months ago. I first noticed that some times when cold, the gearbox would play up in reverse when starting cold ( under 19'C } popping it into reverse and the car would start to uncontrollable surge out of the driveway. this got worse and worse over the next couple of months. however it was ok when the motor warmed up.

Diagnosis the issue just was impossible. I've changed out the wiring a couple of years ago . So I inspected the pigtail and it was all clear of oil. I will do a filter and oil change on the box sooner or later.... lets be honest it will be later. I put my computer on the box and as expected there wasn't any codes in the box.., It was feeling like the lock up clutch circuit was getting pressurised and locking on at idle and as the box was getting warm the tolerances were closing up and the lock up clutch circuit was depressurising.

As a daily driver it can wait. the next issues was jumping a couple teeth on the inlet cam. luckily I got some cam wheels and timing chain hanging around so I popped those in then cranked the motor over.

The motor never really ran properly after that. It was stronger but not just right. I could not put the computer on it so I waited for two weeks ( about 30 starts) and rechecked the motor the timing is good however how ever the for mentioned gearbox issue now check engine light {lean burn code} and high idle.

the high idle increased over the next few weeks getting worse. in park and neutral the idle was 1200 plus rpms, but in drive it fell to under 800. other issues were. over speeding downhills , when before coasting down a hill the car keep it speed and didn't roll away, now it was increasing speed to a point I was constantly on the brakes. some thing not right so got the computer back I popped the computer onto check and adjust the pedal sensor.

well as expected I had a lot of lean burn codes, I also had a large negative correction on the idle mixture. {-4.5 percent) 1250 rpms at idle. Any Adaptations did not achieve my desired result. So I wasn't going to start messing around with looking for a vacuum leak to I checked out the pedal and throttle position sensor. Note I did clean the throttle position sensor about a month before just after the cam chain kit went in. but I wrote up in my job card to do throttle position sensor check on the computer and if faulty replace and do a smoke test for vacuum leaks,

So I checked the pedal out and as expected the pedal was not zeroed. this was a pain it wasn't out by much but it was out. so I checked for adaptions and found out there isn't any. I could not believe there is not a adaption for a pedal sensor zero point. Either the sensor works or its faulty there is no adjustment for w203 (das c3 version) {anyone with a c5 version can let me know if there a zero point adjustment in that version please.}

so my job card reads in order.

high idle
vacuum leak
lean burn issue
gear box fault


1 replace throttle pedal
2 clean throttle body
3 re check pedal and body on computer.
4 use smoke to check for leaks
5 pull gear box and mod lock up circuit
6 service gear box



Any one can add any thing please