P2AD0Reductant Temperature Sensor B Circuit Intermittent
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P2AD0 stands for short interruptions or jumps in the signal of reductant temperature sensor B. The current title reads circuit intermittent only, without erratic. No manufacturer publishes this test. The closest documented logic is GM's tank sensor check P205E in its 2025 DEF controller, which counts a failure when the value moves more than 4 °C within a ten-sample window and needs three such failures out of nine; sensor A has the corresponding code P2046. Because DEF crystallises when it leaks, a slightly damp connector can produce exactly these spikes; vibration loosening a terminal is the other classic cause. Steady faults are reported as P2ACE or P2ACF instead. Clean and dry the connector, check terminal grip and repeat a wiggle test with live data running.
- What you may notice
- Check engine light that appears sporadically
- Jumping DEF temperature in live data
- Likely causes
- LikelyMoisture or DEF residue in the sensor B connector
- PossibleTerminal loosened by vibration
- RareWire breaking intermittently inside the insulation
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €40 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.