Flashing or Full Hot Coolant Gage and Fast Chime

TEST CONDITION(S)
NONE

FAILURE CONDITION(S)
1. Engine is running.
2. Coolant temperature not failed.
3. Engine coolant temperature greater than 126°C (259°F).

ACTION TAKEN
1. Flash the IPC coolant temperature gauge bars.
2. Activate the fast chime.

DESCRIPTION
The PCM provides and internally monitors voltage to the coolant temperature sensor circuit through pin 2B9. As the coolant temperature goes from cold to hot, the sensors resistance goes from high to low, and the voltage level that the PCM detects at pin 2B9 goes from high to low. Every 1 second, the 3CM checks the PCM for the coolant temperature. If the calculated coolant temperature reaches 126 degrees centigrade (i.e. the voltage at pin 2B9 of the PCM drops low enough). and all other failure conditions are met, the IPC will cause the Coolant Temperature Gauge bars to flash (DIGITAL) or peg the coolant gauge full hot (ANALOG) and the BCM will activate the fast chime on the chime module.

DIAGNOSIS
Refer to engine overheat diagnosis in Cooling Systems. Cooling System