"CHECK COOLANT LEVEL" Message

Check Coolant Level Message:

Generator Circuit:

CIRCUIT DESCRIPTION:
This test checks for a low engine coolant condition. The pressurized coolant bottle is equipped with a level switch which closes when coolant level is low. The PCM monitors the state of this switch through CKT 1478 and measures the time that the switch is closed. If the switch is closed for longer than a calculated period of time, the PCM tells the BCM via the data link to turn "ON" the "CHECK COOLANT LEVEL" message.

The calculated period of time before a low coolant condition is recognized is based on vehicle speed and acceleration. The higher vehicle speed and acceleration, the longer the time before a low coolant condition will be recognized.

TEST CONDITION(S):
1. Codes P024 and P075 not set.
2. Engine coolant temperature above 220°C.

FAILURE CONDITION(S):
1. Coolant level input low for between 2.1 and 26.3 seconds (based on vehicle speed and acceleration).

ACTION TAKEN:
1. IPC turns "ON" the "CHECK INFO CENTER" telltale.
2. "CHECK COOLANT LEVEL" message is displayed on the CCDIC for the entire ignition cycle.

NOTES ON FAULT TREE:
1. Physically checking if low coolant level is causing the message.
2. Checking for a shorted coolant level switch.
3. Checking CKT 1478 for a short to ground or if the PCM is bad.