RAM 2500 Truck 4WD V8-5.9L VIN Z LDC (1998)
Thermostat: Testing and Inspection
ON BOARD DIAGNOSTICS
All gasoline powered models are equipped with On-Board Diagnostics for certain cooling system components. Refer to On-Board Diagnostics (OBD)
in the Diagnosis, section of this group for additional information. If the Powertrain Control Module (PCM) detects low engine coolant temperature, it
will record a Diagnostic Trouble Code (DTC) in the PCM memory. Do not change a thermostat for lack of heat as indicated by the instrument panel
gauge or by poor heater performance unless a DTC is present. Refer to the Diagnosis section of this group for other probable causes. For other DTC
numbers, refer to Emission Systems.
The DTC can also be accessed through the DRB scan tool. Refer to the appropriate Powertrain Diagnostic Procedures manual for diagnostic
information and operation of the DRB scan tool.
