P20C5 code meaning
Reductant Heater D Control Circuit/Open
Powertrain system Generic code P20xx codes Check engine light
What P20C5 means
P20C5 covers an open control circuit in reductant heater D, the fourth heating element that only a few SCR layouts carry. Deutz is the one maker found that publishes the code: in its EMR5/MD1 fault list D is the downstream line heater, and P20C5 maps to SPN 520471 with FMI 5, an open or too little current. FCA's 3.0 L EcoDiesel also has a heater 4 (see P20C6), but no public document names P20C5 for it, and vehicle makers give no thresholds. Detection most likely follows the method GM documents for its heaters 1–3, which pinpoints an open with the output switched off, Type A once 2 s have passed. CARB requires output components to be checked for circuit faults. A broken wire, a loose connector or a burnt-out element in the heated downstream line are the likely causes.
P20C5 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 P20C5
- Warning lamp in cold weather
- Dosing delayed while the downstream line thaws
Common causes of P20C5
- Most likelyHeating wire in the downstream DEF line burnt out or broken
- PossibleLoose or corroded heater D connector
- PossibleWire break in the harness to heater D
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Reductant line heater d
What each part of P20C5 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. |
| C5 | The exact fault in that area. |
What to do next
- Note P20C5 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 P20C5
What does P20C5 mean?
P20C5 means "Reductant Heater D Control Circuit/Open". P20C5 covers an open control circuit in reductant heater D, the fourth heating element that only a few SCR layouts carry. It is a generic code, so it means the same on every make.
Is it safe to drive with P20C5?
Drive gently and only to a workshop. With P20C5 the car can go into limp mode (reduced power) to protect itself.
Will P20C5 fail an emissions test?
Yes, it can. P20C5 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 P20C5 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will P20C5 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.