Hi All,
Customer complains of surging and lower power than normal.
Four DTC's:
P0170 (no definition in Multiscan) but is B1 fuel trim.
P0243 Air flap switchover actuator for compressor M16/7.
P0300 B Misfires detected.
P0301 B Misfires cyl 1.
Cleared the codes and took it for a test run.
Definately as customer described and the P0243 code returned.
I removed the switchover actuator, checked it for free operation, tested the motor and tested/cleaned the potentiometer. Reconnected it and confirmed that it was being driven. When the flap was disturbed the controller tried very hard to bring it back to the correct position.
Mindful of the problems dodgy MAFs cause with Mercs in general I took it out and cleaned it. Afterwards I got a peak airflow of 228Kg/H up from 172Kg/H, the driveability was much better but it did still trip a P0243 code.
I'm going to advise the customer to have a new MAF but I'm not certain if it will cure the actuator code or whether that is a seperate problem (Multiscan does not have the facility to do a re-learn on the actuator unfortunately which would have helped).
Nothing I could find in the archives.
Just wondering if I have two problems or only one.
Shaun