OBD-II code · Powertrain (generic)
P04AA Exhaust Pressure Control Valve B Position Sensor Circuit Intermittent or Erratic
Same as P04A6 with intermittent or erratic feedback - typically a connector or harness fault. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
Is it safe to drive with P04AA?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyIntermittent contact at connector
- Less likelyConnector with intermittent contact under vibration
- Less likelyHarness routed against vibrating component
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.8–2 h
- Emissions test
- Likely to fail
- Parts involved
- Exhaust Pressure Position Sensor B, Exhaust Pressure Wiring B
Related codes
- P04A7Exhaust Pressure Control Valve B Position Sensor Circuit Range or Performance
- P04A8Exhaust Pressure Control Valve B Position Sensor Circuit Low
- P04A9Exhaust Pressure Control Valve B Position Sensor Circuit High
- P04ABEVAP System Purge Control Valve B Circuit Open
- P04ACEVAP System Purge Control Valve B Circuit Low
- P04ADEVAP System Purge Control Valve B Circuit High
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.