DTC P21C7 - Reductant Control Module Power Relay Control Circuit Open
WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 2019 Ford Transit-350 HD, 2019 Ford Transit-350, 2019 Ford Transit-250, 2019 Ford Transit-150, and 2019 Ford F-550 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.
DTC DESCRIPTION P21C7 - REDUCTANT CONTROL MODULE POWER RELAY CONTROL CIRCUIT OPEN
| Description: | The PCM carries out a functional key ON, engine running (KOER) self-test for the glow plug system. During that test, the PCM enables the glow plug control module (GPCM) which monitors each individual reductant heater and harness for concerns. When the GPCM detects a concern with a reductant heater relay or the RDHTRPWR circuit, the GPCM sends a message to the PCM which sets this DTC. | ||
| Possible Causes: |
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| Diagnostic Aids: | The presence of this DTC may indicate that 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 . | ||