P20B0Reductant Metering Unit Temperature Sensor Circuit Intermittent/Erratic
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P20B0 flags a metering unit temperature signal that jumps or drops out for brief moments instead of failing steadily. Housing, pump and fluid store a lot of heat, so the real temperature cannot change in leaps; the software treats such steps as a signal defect. Loose terminals, a harness rubbing against the frame near the tank and connectors exposed to road splash and thermal cycling are the main suspects. Since the fault comes and goes, it may well be inactive at the moment of inspection, and wiggling the harness while watching live data helps more than a single resistance reading. No manufacturer documents P20B0 publicly, so the actual jump limits remain unknown.
- What you may notice
- Warning lamp that comes and goes
- Temperature value jumping in live data
- Fault often not reproducible in the workshop
- Likely causes
- LikelyLoose or spread terminal in the module connector
- PossibleHarness chafing intermittently against frame or tank bracket
- PossibleMoisture entering the connector during wet or freezing conditions
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.