P0128

Test 1:

SYMPTOM
P0128-THERMOSTAT RATIONALITY

WHEN MONITORED
The engine running.

SET CONDITION
The PCM predicts a coolant temperature value that it will compare to the actual coolant temperature. If the two coolant temperature values are not within 10 °C (18 °F) of each other an error is detected. Two Trip Fault.

POSSIBLE CAUSES
- Coolant level
- Thermostat