P0170moderate severityPowertrain
Fuel Trim Bank 1
on 2004 Subaru Forester 2.5L H4 · AWD
What this code means
The fuel trim values for Bank 1 are outside the acceptable range, indicating a persistent lean or rich condition.
Symptoms
- Check Engine Light
- Poor fuel economy
- Rough idle
- Hesitation
Common causes
- Vacuum leak
- Faulty O2 sensor
- Fuel pressure issue
- MAF sensor problem
- Exhaust leak
Diagnostic steps
- Check long-term fuel trim values
- Inspect for vacuum leaks
- Test fuel pressure
- Test MAF sensor
- Check for exhaust leaks
Repair notes
Diagnose and correct the underlying lean or rich condition.
Other Powertrain codes on this vehicle
P0001
Fuel Volume Regulator Control Circuit/Open
P0002
Fuel Volume Regulator Control Circuit Range/Performance
P0003
Fuel Volume Regulator Control Circuit Low
P0004
Fuel Volume Regulator Control Circuit High
P0010
Intake Camshaft Position Actuator Circuit/Open Bank 1
P0011
Intake Camshaft Position Timing Over-Advanced Bank 1
P0012
Intake Camshaft Position Timing Over-Retarded Bank 1
P0013
Exhaust Camshaft Position Actuator Circuit/Open Bank 1
P0014
Exhaust Camshaft Position Timing Over-Advanced Bank 1
P0015
Exhaust Camshaft Position Timing Over-Retarded Bank 1