P205AReductant Tank Temperature Sensor A Circuit
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P205A is the general circuit code for the temperature sensor inside the DEF tank, usually built into the level or heater unit; the separate sensor in the supply path uses P2042 ff. Deutz assigns the tank temperature (J1939 SPN 3031) to P205A: failure type 13 for an open circuit, 21 and 22 for values under or over the valid range, while the SCR-side DEF sensor (SPN 4337) stays with P2042. VW's 2014 Touareg (CNRB) stores P205A when the signal exceeds 4.70 V, i.e. the high side that an open NTC circuit produces, and keeps the low side (below 0.30 V) for P205C. Other makers split these faults into P205C and P205D. The tank temperature decides when the tank heater runs, so a fault can mean frozen DEF and an SCR warning in winter.
- What you may notice
- MIL and DEF warning
- Tank heating not working in frost
- Speed or restart limit on some models
- Likely causes
- LikelyOpen circuit or loose tank connector
- PossibleTank temperature sensor in the sender unit defective
- PossibleCorroded terminals from DEF exposure
- 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: €60 – €1,200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.