Jeep Cherokee

 Service Manual

Cooling system » Diagnosis and testing
On-board diagnostics (OBD)

COOLING SYSTEM RELATED DIAGNOSTICS

The Powertrain Control Module (PCM) has been programmed to monitor the certain following cooling system components:

•  If the engine has remained cool for too long a period, such as with a stuck open thermostat, a Diagnostic Trouble Code (DTC) can be set.
•  If an open or shorted condition has developed in the relay circuit controlling the electric radiator fan, a Diagnostic Trouble Code (DTC) can be set.

If the problem is sensed in a monitored circuit often enough to indicate an actual problem, a DTC is stored. The DTC will be stored in the PCM memory for eventual display to the service technician. (Refer to Group 25, Emission Control Systems for proper procedures)

ACCESSING DIAGNOSTIC TROUBLE CODES

To read DTC's and to obtain cooling system data, refer to Group 25, Emission Control Systems for proper procedures.

DRB scan tool

For operation of the DRB scan tool, refer to the appropriate Powertrain Diagnostic Procedures service manual.

On-board diagnostics (OBD)

Accessory drive belt diagnosis

Preliminary checks

Radiator coolant flow check

Cooling system-testing for leaks

Viscous fan drive

Electric cooling fan

Radiator cap-to-filler neck seal-pressure relief check

Radiator cap-pressure testing

Coolant-low level aeration

Deaeration