Inspect the charge-air cooler fins for obstructions to airflow. Remove obstructions such as a winterfront or
debris. Manually lock the shutters in the open position, if equipped.
Lock the fan drive in the ON mode to prevent erratic test results. This can be done by installing a jumper wire
across the temperature switch.
Use INSITE’M electronic service tool to monitor the intake manifold air temperature sensor and ambient air
temperature sensor values.
Perform a road test with the engine at peak power and a vehicle speed of 48 km/h (30 mph] or greater.
Record the intake manifold temperature and the ambient air temperature.
Calculate the differential temperature:
Intake manifold temperature – ambient air temperature = differential temperature.
• Maximum Differential Temperature = 21 °C [38°F] .
If the temperature differential is greater than the specifications, check the charge air cooler for dirt and
debris on the fins and clean as necessary. If the problem still exists, check the charge air cooler for debris in the fins
or between the charge air cooler and radiator. Confirm full- fan engagement.
