B450

Coolant Temp Sensor Circuit:

CIRCUIT DESCRIPTION:
Code B450 is designed to disengage the A/C compressor clutch if the engine coolant temperature (BCM data parameter BD21) exceeds 123°C. The A/C compressor will re-engage and the code will be stored as a history code when the engine coolant temperature falls below 117°C. If Code P014 or Code B441 is also stored, diagnose that code first. Engine overheating may accompany this code. If coolant temperature exceeds normal operating range, check for sources of overheating. Carefully check all sources of intermittent engine overheating such as faulty belt or belt tension, coolant level and restrictions, faulty hoses, or routings. If coolant temperature displayed exceeds actual temperature as measured with a radiator coolant temperature testing device, the coolant temperature sensor may be faulty.

Possible causes for a false Code B450 are:

^ Short to ground on CKT 476.
^ Faulty Coolant Temperature Sensor.