The P20C5: Reductant Heater ‘D’ Control Circuit/Open refers to an issue where the control circuit for reductant heater ‘D’ has an open circuit. This means there is a disconnection or break in the wiring, which prevents the heater from functioning. The issue could stem from wiring problems, a defective heater, or a malfunctioning control module.
P20C5 – Quick Overview
| Code | Information |
|---|---|
| Meaning | P20C5: Reductant Heater ‘D’ Control Circuit/Open |
| Is it serious? | Yes, this can cause the reductant system to malfunction, leading to emissions control issues. |
| Possible causes | – Open circuit in the reductant heater ‘D’ control circuit – Faulty reductant heater ‘D’ – Faulty control module |
| How to diagnose? | – Inspect the wiring for open circuits – Test reductant heater ‘D’ – Check the control module functionality |
P20C5 Meaning
The P20C5 fault code indicates that the control circuit for reductant heater ‘D’ is open, meaning that there is a break or disconnection in the circuit. This prevents the heater from working, which can impact the vehicle’s emissions reduction system. The issue could be caused by faulty wiring, a defective heater, or a problem with the control module that manages the heater.
Step-by-step diagnostic guide
| Action | Description | Tools Needed |
|---|---|---|
| Check for Other Codes | Use an OBD-II scanner to look for other related codes that might help with diagnosis. | OBD-II Scanner |
| Inspect Wiring for Open Circuits | Visually inspect the wiring for open circuits, breaks, or disconnections in the control circuit for reductant heater ‘D’. | Flashlight, Multimeter |
| Test Reductant Heater ‘D’ | Use a diagnostic tool to test the functionality of reductant heater ‘D’ and ensure it is operating properly. | Diagnostic Tool, Multimeter |
| Check the Control Module | Verify the control module is functioning correctly and not contributing to the open circuit problem. | Diagnostic Tool |
| Repair or Replace Wiring/Heater | If an open circuit is found, repair the wiring or replace the heater as necessary. | Wiring Kit, Replacement Heater |
| Clear the Code and Test Drive | After repairs, clear the code using an OBD-II scanner and test drive the vehicle to ensure the problem is resolved. | OBD-II Scanner, Vehicle Manual |
| Recheck for Codes | After the test drive, rescan the vehicle to ensure the P20C5 code does not reappear. | OBD-II Scanner |
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