DTC P21DD (DCU) - Reductant Heater A Current Too Low
WARNING: This page is about a different car, the 2020 Ford F-550 Super Duty, 2020 Ford F-450 Super Duty, 2020 Ford F-350 Super Duty, 2020 Ford F-250 Super Duty, and 2020 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.
DTC DESCRIPTION P21DD (DCU) - REDUCTANT HEATER A CURRENT TOO LOW
| Description: | This DTC sets when the reductant dosage control module (DCU) detects insufficient current draw from the reductant tank heater. | ||
| Possible Causes: |
|
||
| Diagnostic Aids: | The presence of this DTC may indicate the vehicle is operating in derate mode and may experience a loss of power. After repair, the vehicle may still display a system warning message. Drive the vehicle until the system warning message has cleared from the instrument cluster message center. | ||
| Application | Key On Engine Off | Key On Engine Running | Continuous Memory |
| All | GO to PINPOINT TEST RH . | ||