Test Notes

NOTE: You should enter this pinpoint test only when you have been directed here from diagnostic routines.

To prevent the replacement of good components, be aware that the following non-EEC areas may be at fault:
- Coolant level
- Cooling system
- Cooling fan
- Water pump drive belt
- Engine operating temperature
- Engine oil level
- Thermostat
- Air cleaner duct
- Ambient temperature

NOTE: Engine coolant temperature must be greater than 10°C (50°F) to pass the KOEO Self-Test and greater than 82°C (180°F) to pass the KOER Self-Test. To accomplish this, the engine should be at normal operating temperature. Ambient temperature should be above 10°C (50°F) to receive acceptable input from the Intake Air Temperature (IAT) sensor.

This pinpoint test is intended to diagnose only the following:
- Intake Air Temperature (IAT) sensor
- Engine Coolant Temperature (ECT) sensor
- Harness circuits: IAT, ECT, and SIG RTN
- Powertrain Control Module (PCM)

OPERATION
The IAT and ECT sensors change resistance in response to temperature. IAT and ECT sensor resistance decreases as the surrounding temperature increases providing a signal to the PCM indicating the temperature of the intake air or engine coolant.