P1550moderate severityPowertrain
Idle Speed Control Error
on 1997 BMW 528i 2.8L I6 M52 · RWD
What this code means
The DME detected that the engine idle speed is outside the acceptable range and cannot be corrected by the idle speed control system. The engine speed deviates from the target idle RPM by more than the allowable margin.
Symptoms
- Rough or unstable idle
- Idle speed too high or too low
- Engine stalling
- Check Engine Light
Common causes
- Vacuum leak
- Dirty throttle body
- Faulty idle air control valve
- Incorrect base idle setting
- Air intake leak after MAF sensor
Diagnostic steps
- Check for vacuum leaks with smoke machine
- Clean throttle body
- Test idle air control valve
- Perform idle adaptation with scan tool
- Check intake system for leaks
Repair notes
Repair vacuum leaks and clean throttle body; perform idle speed adaptation.
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Other Powertrain codes on this vehicle
29CC
Misfire Cylinder 1
29CD
Misfire Cylinder 2
29CE
Misfire Cylinder 3
29CF
Misfire Cylinder 4
29D0
Misfire Cylinder 5
29D1
Misfire Cylinder 6
29D2
Misfire Cylinder 7
29E0
Lambda Additive/Idle Adaptation Limit, Bank 1
29E1
Lambda Additive/Idle Adaptation Limit, Bank 2
29E2
Lambda Multiplicative Part-Load Adaptation Limit, Bank 1