P20B4 Possible Causes
- Faulty reductant heater coolant control valve
- Reductant heater coolant control valve harness is open or shorted
- Poor electrical connection in the reductant heater coolant control valve circuit
What Does It Mean?
How to Fix Code P20B4
Check the “possible causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.
Possible Symptoms
Check engine light on (or service engine soon warning light)
P20B4 Meaning
Reductant heater coolant control valve circuit high is the generic description for code P20B4, but the manufacturer may have a different description.