Flashing Coolant Gauge and Chime

CTS Circuit:

DESCRIPTION:

The ECM provides and internally monitors voltage to the
coolant temperature sensor circuit through pin 3D4. As the coolant temperature goes from cold to hot, the sensor's resistance goes from high to low, and the voltage level the ECM detects at pin 3D4 goes from high to low. Every 1.0 second, the BCM checks the ECM for the coolant temperature. If the calculated coolant temperature reaches 126°C (i.e. the voltage at pin 3D4 of the ECM drops low enough), and all other failure conditions are met, the IPC will cause the coolant temperature gauge bars to flash, and the BCM will activate the fast chime on the chime module.

TEST CONDITIONS:

NONE.

FAILURE CONDITIONS:

1. Engine is running.
2. Engine coolant temperature greater than 126°C.
3. Coolant temperature not failed.

ACTION TAKEN:

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