P205A code meaning
Reductant Tank Temperature Sensor A Circuit
Powertrain system Generic code P20xx codes Check engine light
What P205A means
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.
P205A at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P205A
- MIL and DEF warning
- Tank heating not working in frost
- Speed or restart limit on some models
Common causes of P205A
- Most likelyOpen circuit or loose tank connector
- PossibleTank temperature sensor in the sender unit defective
- PossibleCorroded terminals from DEF exposure
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Reductant tank temperature sensorReductant tank
What each part of P205A means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 0 | Area: fuel and air metering and auxiliary emission controls. |
| 5A | The exact fault in that area. |
What to do next
- Note P205A and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P205A
What does P205A mean?
P205A means "Reductant Tank Temperature Sensor A Circuit". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with P205A?
Drive gently and only to a workshop. With P205A the car can go into limp mode (reduced power) to protect itself.
Will P205A fail an emissions test?
Yes, it can. P205A is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P205A to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will P205A clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.