OBD-II code · Network
U05A5 Invalid Data Received From NH3 Sensor
A receiving module detected implausible data from the ammonia (NH3) slip sensor downstream of the SCR. Concentration values fail plausibility checks and are rejected.
Is it safe to drive with U05A5?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyModule internal fault or sensor input drift
- PossibleSoftware version mismatch after replacement
- Less likelyGateway module routing CAN messages incorrectly
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.5–3 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Nh3 Sensor
Related codes
- U05A2NOx Sensor B Received Invalid Data From ECM/PCM
- U05A3Invalid Data Received From Reductant Quality Module
- U05A4Particulate Matter Sensor Received Invalid Data From ECM/PCM
- U05A6Invalid Data Received From Reductant Heater Control Module
- U05A7Invalid Data Received From Safety Integration Control Module
- U05A8Invalid Data Received From NOx Sensor C
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.