Heater active in off mode
•Check for DTC 033E, Coolant heater contactor supply short circuit to 24V. If DTC 033E can be found, perform actions for that error code. •Disconnect connectors H32-A and H32-B. Measure resistance on the component between H32-A-A and H32-A-C. If the resistance is <OL, change heater H32. •Measure the resistance on the component between the pins H32-A3 and H32-A4. The resistance should be around 2.7kohm at 20°C. •If the resistance is below 660ohm change the heater. •Leave H32-A and H32-B disconnected. Disconnect the connector E81-C. Turn on the ignition with the diesel engine off. Measure the voltage on the cable harness over E81-C10 and E81-C14. If the voltage is >0V change the cable. •Change BMU(E81).
What you'll see
No driver-visible symptom recorded.
System reaction
• VOR, the hybrid system will not work since the battery will not be engaged. The DCC will not receive VCB-power and the 24-volt system will drain the 24-volt batteries. • Red stop lamp, "24V batteries not charged" and "Hybrid System Fault" is shown in ICL
Diagnostic depth
Heater temperature feedback reports rising temperature above level at which heater is not allowed or temperature does not decrease within reasonable time after overheat. (heater on without heating request).
•Relay in heater stuck •Short circuit in heater •Cable harness defect