P2045 code meaning
Reductant Temperature Sensor A Circuit High
Powertrain system Generic code P20xx codes Check engine light
What P2045 means
P2045 covers the opposite end: the voltage of reductant temperature sensor A is higher than any real temperature would produce. With an NTC element this reads as very cold, which is what an interrupted ground, a disconnected plug or a signal wire touching battery voltage cause. Deutz files P2045-00 as a short to battery for the DEF sensor outside the tank (SPN 4337); an open circuit gets its own entry, P2042-13. The tank temperature sensor counts separately, with its high fault under P205D. As no maker publishes thresholds for P2045, the CARB rule on input circuit monitoring (section (f)(15.2.1) of 13 CCR 1968.2) is the frame. A false cold value may keep the heater running and delay dosing after start. Check the plug, the ground and the sensor resistance at a known temperature.
P2045 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 P2045
- MIL and DEF warning
- Scan tool shows DEF temperature near the lower limit
- Dosing may start late after a cold start
Common causes of P2045
- Most likelyOpen sensor ground or unplugged connector
- PossibleSignal wire shorted to battery or supply voltage
- PossibleSensor element open internally
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Reductant temperature sensor
What each part of P2045 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. |
| 45 | The exact fault in that area. |
What to do next
- Note P2045 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 P2045
What does P2045 mean?
P2045 means "Reductant Temperature Sensor A Circuit High". P2045 covers the opposite end: the voltage of reductant temperature sensor A is higher than any real temperature would produce. It is a generic code, so it means the same on every make.
Is it safe to drive with P2045?
Drive gently and only to a workshop. With P2045 the car can go into limp mode (reduced power) to protect itself.
Will P2045 fail an emissions test?
Yes, it can. P2045 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 P2045 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2.5 hours of work. This is a job for a workshop.
Will P2045 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.