For 1990-2009 cars

## Cooling System Diagnosis Overheating Diagnostic Check

### Preliminary Overheating Diagnostic Check

1. Does overheating occur while pulling a trailer?

• | Is the trailer within the recommended towing payload?

• | Is the vehicle equipped with a heavy duty cooling package?

2. Is the vehicle equipped with an add-on, or aftermarket, air conditioning system? If so, was a heavy duty radiator installed?
3. Is overheating occurring after prolonged idle in gear with the A/C system operating?
4. Is overheating occurring after prolonged driving in slow city traffic, or traffic jams?

If any of the above conditions apply, instruct the operator on driving techniques that would reduce the possibility of engine overheating.

If none of the above conditions apply, refer to Engine Overheating .

## Cooling System Diagnosis Low Coolant Lamp On

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Check for a faulty low coolant sensor. Is the sensor faulty? | -- | Go to Step 2 | Go to Step 3
2 | Replace the sensor. Refer to Electrical Diagnosis. Does the low coolant lamp continue to stay on? | -- | Go to Step 3 | System OK
3 | Check for a faulty circuit. Is the circuit faulty? | -- | Go to Step 4 | --
4 | Repair the circuit. Refer to Electrical Diagnosis. Does the lamp stay on? | -- | -- | System OK