Audi
Older VW code: fuel trim lean (multiplicative), bank 1. The engine is adding fuel across the rev range.
P1128 fault code: what it means
P1128: Older VW code: fuel trim lean (multiplicative), bank 1. The engine is adding fuel across the rev range.
Usual causes, most likely first
- faulty MAF sensor
- air leak after the MAF
- oxygen sensor fault
- weak injectors or low fuel pressure
P1128 by make
Porsche
Mixture adaptation, idle range, bank 1: running lean at idle. Air/oil separator, oil filler cap or intake leaks are typical.
Skoda
Older VW code: fuel trim lean (multiplicative), bank 1. The engine is adding fuel across the rev range.
Volkswagen
Older VW code: fuel trim lean (multiplicative), bank 1. The engine is adding fuel across the rev range.
What the repair usually costs
- 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
- Parking sensor replace, one sensorNZ$130–NZ$520 · A$130–A$510
Not sure what P1128 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.