P21CC
Reductant Control Module Supply Voltage High
P21CC is an OBD-II diagnostic trouble code meaning: Reductant Control Module Supply Voltage High. Common causes: problems with the generator (voltage in the on-board network is too high), reagent control module malfunction. Estimated repair cost: $56–278.
Symptoms
- Check Engine light comes on
- Reduced engine power
- Increased fuel consumption
- SCR system error message on dashboard
- Increased NOx emissions
Causes
- Problems with the generator (voltage in the on-board network is too high)
- Reagent control module malfunction
- Damage to the wiring harness to the module
- Short circuit in power supply
- Relay or fuse problems
How to Fix
- Check the voltage in the on-board network (should be 13.5-14.5V with the engine running)
- Inspect the wiring harness to the module for damage
- Check fuses and relays in the module power circuit
- Test the reagent control module
- If necessary, replace the control module
Related codes
Error P21CC by Vehicle Brand
FAQ
What does the P21CC code mean?
P21CC is an OBD-II diagnostic trouble code that indicates: Reductant Control Module Supply Voltage High
What causes a P21CC error code?
The most common causes of P21CC include: Problems with the generator (voltage in the on-board network is too high); Reagent control module malfunction; Damage to the wiring harness to the module; Short circuit in power supply.
How do I fix a P21CC diagnostic trouble code?
To fix P21CC: Check the voltage in the on-board network (should be 13.5-14.5V with the engine running). Inspect the wiring harness to the module for damage. Check fuses and relays in the module power circuit. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with P21CC?
Yes, but get it checked soon
How much does it cost to fix P21CC?
The estimated repair cost for P21CC is $56–278. Actual cost depends on your vehicle, location, and labor rates.
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