Mercedes-Benz
Fuel trim fault, bank 1 (mixture too rich or too lean). On Mercedes most often a dirty or failing mass air flow (MAF) sensor.
P0170 fault code: what it means
P0170: Bank 1 fuel trim is out of range; the engine computer cannot correct the air-fuel mixture.
Usual causes, most likely first
- vacuum leak
- dirty or faulty MAF sensor
- faulty front O2 sensor
- fuel pressure too high or too low
P0170 by make
What the repair usually costs
- ABS / brake booster actuator replacement (Toyota hybrid)NZ$1,280–NZ$3,430 · A$1,140–A$3,090
- Air-fuel ratio / front O2 sensor replace (upstream)NZ$270–NZ$750 · A$260–A$730
- O2 sensor replace (downstream / after cat)NZ$180–NZ$480 · A$180–A$460
- MAF (mass air flow) sensor replaceNZ$170–NZ$660 · A$160–A$600
Not sure what P0170 means on your car? Ask Credov.
Before you clear it
Write the code down or photograph the scanner first. A code that comes straight back after clearing points to a fault that is still there. A car whose codes were cleared just before you arrived may be hiding one: the scanner's readiness monitors show "not ready" for a while after codes are cleared.
Researched by Credov from manufacturer and workshop sources. A fault code points to where a fault may be; a workshop confirms it with a diagnosis. Browse all fault codes.