P205C code meaning
Reductant Tank Temperature Sensor A Circuit Low
Powertrain system Generic code P20xx codes Check engine light
What P205C means
P205C reports the DEF tank temperature signal at the bottom of its range. For voltage-read NTC sensors that means implausibly hot: Ford's 2023 diesels set it below 0.165 V, VW's Touareg below 0.30 V, GM's 2025 DEF controller below 0.3 V (about 75 °C) and GM's 2018 diesel table below 200 Ω, each as short to ground. Careful with older GM trucks: on the 6.6L LML and the 2014 Cruze the value arrives as a CAN raw value, and Low means a raw value under 1, i.e. −55 °C and over 1200 kΩ, the cold side (Type A, 3 s). Ford bulletin 18-2190 replaces the reductant heater and sender assembly on 2011–2015 6.7L Super Duty when P205C appears with P2043, and Hino has P205B to P205D checked before blaming the coolant valve. The high end is P205D.
P205C at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 2.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P205C
- MIL and DEF warning
- Tank temperature in live data stuck at an extreme
- Tank heater not working in frost
Common causes of P205C
- Most likelySignal wire shorted to ground
- PossibleFaulty sensor in the heater/sender assembly
- PossibleDEF in the connector bridging the terminals
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Reductant tank temperature sensor
What each part of P205C 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. |
| 5C | The exact fault in that area. |
What to do next
- Note P205C 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 P205C
What does P205C mean?
P205C means "Reductant Tank Temperature Sensor A Circuit Low". P205C reports the DEF tank temperature signal at the bottom of its range. It is a generic code, so it means the same on every make.
Is it safe to drive with P205C?
Drive gently and only to a workshop. With P205C the car can go into limp mode (reduced power) to protect itself.
Will P205C fail an emissions test?
Yes, it can. P205C 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 P205C to fix?
Difficulty: medium. A typical repair takes 0.5 to 2.5 hours of work. This is a job for a workshop.
Will P205C clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.