What it means
A receiving module detected implausible data from the reductant heater module. Heater current/voltage or temperature values fail plausibility checks and are rejected.
At a glance
- Usually lights the warning light of the system that lost communication
- Affects emissions; the car can fail an emissions test
How it works
The reductant heater control module manages heating of the DEF/AdBlue system and reports heater electrical and temperature information to other vehicle modules. This code sets when a receiving module judges those reported values implausible and rejects them, which can leave reductant heating status uncertain.
Common causes
Most likely first.
- Module internal fault or sensor input drift
- Software version mismatch after replacement
- Gateway module routing CAN messages incorrectly
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
How to diagnose it
- Save freeze-frame data and scan all modules for reductant heater, DEF/AdBlue, and communication codes before clearing anything.
- Review live heater status, reported current or voltage, and temperature values to identify which data is implausible or absent.
- With the system safely powered down as specified by the manufacturer, inspect the heater module connectors, harness, power, ground, and CAN wiring for damage or corrosion.
- Check for related heater, temperature-sensor, or supply faults that could explain inconsistent values.
- Confirm that the reductant heater module, receiving module, and gateway software and configuration match, especially following replacement.
- If wiring, supply, and configuration pass checks, follow manufacturer-approved network tests to isolate the heater control module, receiving module, or gateway.
Common fixes
- Repair damaged heater-module wiring, CAN connections, grounds, or corroded terminals.
- Correct an associated heater supply or temperature-sensing fault identified by diagnosis.
- Install the compatible software or configuration for a replaced reductant heater module or gateway.
- Replace the confirmed faulty heater control module, gateway, or receiving module.
Can I keep driving?
If there are no powertrain warnings or symptoms, a short cautious trip for diagnosis may be possible, but cold-weather operation can expose a reductant heating problem and affect emissions-system operation. Stop if the vehicle warns of a starting restriction, loses power, or enters limp mode.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.