P20B0 code meaning
Reductant Metering Unit Temperature Sensor Circuit Intermittent/Erratic
Powertrain system Generic code P20xx codes Check engine light
What P20B0 means
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.
P20B0 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor1 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P20B0
- Warning lamp that comes and goes
- Temperature value jumping in live data
- Fault often not reproducible in the workshop
Common causes of P20B0
- Most 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
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Reductant metering unitReductant metering temp sensor
What each part of P20B0 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. |
| B0 | The exact fault in that area. |
What to do next
- Note P20B0 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 P20B0
What does P20B0 mean?
P20B0 means "Reductant Metering Unit Temperature Sensor Circuit Intermittent/Erratic". P20B0 flags a metering unit temperature signal that jumps or drops out for brief moments instead of failing steadily. It is a generic code, so it means the same on every make.
Is it safe to drive with P20B0?
Drive gently and only to a workshop. With P20B0 the car can go into limp mode (reduced power) to protect itself.
Will P20B0 fail an emissions test?
Yes, it can. P20B0 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 P20B0 to fix?
Difficulty: medium. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will P20B0 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.