For 1990-2009 cars only
Circuit Description
The PCM uses the ECT sensor to detect when the engine is running too hot. This condition occurs when the engine coolant temperature is more than 131° C (268°F). When the engine is overheated, DTC P1258 will set. The PCM will disable two groups of four cylinders by turning OFF the fuel injectors. By switching between the two groups of cylinders, the PCM is able to reduce the temperature of the coolant.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
| • | The PCM detects an engine over temperature condition. |
| • | The engine coolant temperature is more than 131°C (268°F). |
Action Taken When the DTC Sets
| • | The PCM will illuminate the malfunction indicator lamp (MIL) during the first trip in which the diagnostic test runs and fails. |
| • | The PCM will signal the instrument panel cluster (IPC) to turn ON the Service Engine Cooling System Message. |
| • | The PCM will alternately disable two groups of four cylinders by turning OFF the fuel injectors. |
| • | The PCM will store the conditions present when the DTC set as Freeze Frame and Fail Records data. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn the MIL OFF after three consecutive trips in which the diagnostic runs and passes. |
| • | The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC can be cleared by using the scan tool Clear DTC Information function. |
Step | Action | Values | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||||||||
2 | Are any of the following DTCs set?
| -- | ||||||||
3 | Test the engine cooling fans for proper operation. Are the engine cooling fans operative? | -- | Go to Diagnostic System Check in Engine Cooling |
