Fix P20BC: STEP-BY-STEP diagnostic GUIDE!

The P20BC: Reductant Heater ‘A’ Control Circuit High refers to a condition where the voltage in the control circuit for reductant heater ‘A’ is higher than expected. This could indicate an electrical issue, such as excessive voltage supply to the heater, or problems with the heater itself or the control module.

P20BC – Quick Overview

CodeInformation
MeaningP20BC: Reductant Heater ‘A’ Control Circuit High
Is it serious?Yes, this can cause improper operation of the reductant heater, which is essential for emissions control.
Possible causes– High voltage in the reductant heater ‘A’ control circuit
– Faulty heater
– Faulty control module
How to diagnose?– Measure voltage in the heater control circuit
– Test reductant heater ‘A’
– Check the control module functionality

P20BC Meaning

The P20BC fault code indicates that the control circuit for reductant heater ‘A’ is experiencing a high voltage condition. This can cause the heater to malfunction, affecting the vehicle’s ability to manage emissions effectively. The issue could be due to electrical faults, a malfunctioning heater, or a problem with the control module responsible for regulating the heater.

Step-by-step diagnostic guide

ActionDescriptionTools Needed
Check for Other CodesUse an OBD-II scanner to check for any related codes that may provide additional information about the problem.OBD-II Scanner
Measure Voltage in the Heater Control CircuitUse a multimeter to measure the voltage in the control circuit for reductant heater ‘A’. Ensure the voltage is within the manufacturer’s specifications.Multimeter
Test Reductant Heater ‘A’Test the functionality of reductant heater ‘A’ using a diagnostic tool to ensure it is not drawing too much power.Multimeter, Diagnostic Tool
Inspect the Control ModuleCheck the control module to ensure it is functioning properly and not supplying excessive voltage to the heater.Diagnostic Tool
Repair or Replace Wiring/HeaterIf high voltage is detected, inspect the wiring for faults and repair or replace reductant heater ‘A’ if needed.Wiring Kit, Replacement Heater
Clear the Code and Test DriveAfter making repairs, clear the code with an OBD-II scanner and test drive the vehicle to confirm the issue is resolved.OBD-II Scanner, Vehicle Manual
Recheck for CodesAfter the test drive, rescan the vehicle to ensure the P20BC code does not return.OBD-II Scanner
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