Possible causes – Faulty Viscous/Cabin Heater Relay– Viscous/Cabin Heater Relay harness is open or shorted– Viscous/Cabin Heater Relay circuit poor electrical connection When is the obd code mean? The ECM has detected an excessive current condition on the Viscous/Cabin Heater Relay control circuit Symptoms – Engine Light ON (or Service Engine Soon Warning Light)