DESCRIPTION:
Diesel exhaust fluid (DEF) coolant valve circuit failed open.

MONITORED PARAMETER:
DEF coolant valve.

TYPICAL ENABLING CONDITIONS:
Always enabled

MONITOR SEQUENCE:
None

EXECUTION FREQUENCY:
Always enabled

TYPICAL DURATION:
Two seconds

DASH LAMPS:
1. MIL
2. CEL

ENGINE REACTION:
Derate 10%

VERIFICATION:
Engine Idle: One minute.

NOTE: If code not active, release vehicle to customer.

PROBABLE CAUSES:
1. DEF coolant valve harness connector.
2. Wiring between DEF coolant valve harness connector and the 120-pin ECM connection.