OBD-II DTC · POWERTRAIN · Severity: MEDIUM
P0174: System Too Lean (Bank 2)
Excessive positive fuel trim correction on Bank 2 cylinder bank.
| DTC Code | P0174 |
|---|---|
| Standard Definition | System Too Lean (Bank 2) |
| Subsystem | POWERTRAIN |
| Urgency / Severity | MEDIUM |
| Standard Reference | SAE J2012 / ISO 15031-6 |
1. Symptoms
- Rough idle
- Hesitation under load
- MIL illuminated
2. Common Root Causes
- Intake plenum or vacuum leak affecting Bank 2
- Contaminated MAF sensor
- Weak fuel pump or clogged Bank 2 injectors
3. Diagnostic Procedure
- Compare Bank 1 and Bank 2 LTFT values at idle and 2,500 RPM
- Inspect intake boots and PCV breather lines
- Measure fuel rail pressure under load