Engine Error
P0171
System Too Lean (Bank 1)
Severity
Medium
Symptoms
Rough idling, engine hesitating, decreased gas mileage
Common Causes
- Dirty MAF sensor
- Vacuum leaks
- Clogged fuel filter
- Failing fuel pump
How to Fix
- 1 Clean MAF sensor
- 2 Perform smoke test for leaks
- 3 Replace fuel filter
- 4 Test fuel pump pressure
Estimated Repair Cost
USD
$50
–
$800
MAF cleaning: $50; Fuel pump replacement: $400 - $800