OBD-II code · Powertrain (generic)
P04A1 Exhaust Pressure Control Valve B Low
Same as P049F with the control line shorted to ground.
Is it safe to drive with P04A1?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyControl line shorted to ground
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–3.5 h
- Emissions test
- Likely to fail
- Parts involved
- Exhaust Pressure Valve B
Related codes
- P0477Exhaust Pressure Control Valve A Low
- P049EEGR B Control Position Exceeded Learning Limit
- P049FExhaust Pressure Control Valve B
- P04A0Exhaust Pressure Control Valve B Range or Performance
- P04A2Exhaust Pressure Control Valve B High
- P04A3Exhaust Pressure Control Valve B Intermittent
- P04A4Exhaust Pressure Control Valve B Stuck Open
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.