P20FC reports a low electrical level in reductant-pump B control. Understand why low electrical input does not itself establish low reductant pressure.
Meaning, symptoms, causes and checks
P20FC concerns reductant pump B control circuit. The monitor reports an electrical level below its expected range. B identifies the named pump circuit. The code does not equate a low electrical control level with low reductant pressure.
Affected system: Reductant dosing and SCR aftertreatment
Symptoms
- Warning light may illuminate
- Related system function may be impaired
- Vehicle-specific symptoms vary
Possible causes
- Implausible sensor or switch signal, poor ground, connector corrosion, or wiring damage
- Related wiring, connector, power or ground fault
- Vehicle-specific mechanical or control issue
What to check
- Record stored and pending codes and freeze-frame data
- Compare the named sensor or switch signal with actual operating conditions; inspect the connector, reference supply, ground and harness.
- Confirm measured values against the vehicle service information
- Retest under the conditions that set the code
- Compare the named sensor or switch signal with actual operating conditions; inspect the connector, reference supply, ground and harness.
- Repair the verified cause and confirm the code does not return
Also written as: P20FC-00, P20FC00 (some scan tools add the fault-type byte, e.g. -00).