What P0174 Means
Same lean-mixture issue as P0171, but detected on Bank 2 — the engine control module has run out of correction it's allowed to apply to compensate for excess air on that bank.
Common Causes
- Vacuum leak on the Bank 2 side
- Failing mass airflow (MAF) sensor
- Weak fuel pump or low fuel pressure
- Clogged fuel injectors on Bank 2
- Exhaust leak upstream of the Bank 2 oxygen sensor
Symptoms You Might Notice
- Rough or high idle
- Hesitation on acceleration
- Check engine light on
- Reduced fuel economy
What to Check First
- 1
Inspect vacuum hoses and intake gaskets on the Bank 2 side
- 2
Check the MAF sensor
- 3
Test fuel pressure
- 4
Check for exhaust leaks upstream of the Bank 2 oxygen sensor