P1258

CIRCUIT DESCRIPTION
In order to reduce the engine temperature the PCM has the ability to disable a number of fuel injectors during an engine over temperature condition. The PCM considers the engine over temperature whenever the ECT reaches a predetermined temperature. This DTC sets in order to show that the PCM detected an over temperature condition and that the system engaged the protection mode.

CONDITIONS FOR RUNNING THE DTC
^ DTCs P0117, P0118, P0125 are not set.
^ The engine is running.

CONDITIONS FOR SETTING THE DTC
^ The engine coolant temperature is more than 132°C (270°F).
^ The above conditions present for more than 10 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM illuminates the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.
^ The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Freeze Frame and/or the Failure Records.
^ The PCM alternately disables four fuel injectors.

Diagnostic Chart:

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM turns the Malfunction Indicator Lamp (MIL) OFF after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
^ A last test failed (current DTC) clears when the diagnostic runs and does not fail.
^ A History DTC clears after 40 consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures.
^ Use a scan tool in order to clear the MIL/DTC.

DIAGNOSTIC AIDS

IMPORTANT:
^ Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing/replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion into the PCM.
^ For any test that requires probing the PCM or a component harness connector use the J 35616-A connector test adapter kit. Using this kit prevents damage to the harness/component terminals. Refer to Using Connector Test Adapters in Diagrams.

The PCM enables the Engine Coolant Over temperature mode when coolant temperature exceeds 132°C (270°F). Engine damage still could occur if the customer operates the vehicle too long in an overheat condition. Ensure no engine mechanical conditions exists after the overheat condition is repaired.

If an overheating condition exists, repair the overheat condition and change the engine oil and filter.

Refer to Engine Overheating in Engine Cooling, and Engine Oil and Oil Filter Change in Engine Mechanical 5.7L.

For an intermittent condition, refer to Symptoms. Symptom Related Diagnostic Procedures

TEST DESCRIPTION

Diagnostic Chart:

The numbers below refer to the step numbers on the diagnostic table.
1. A cooling system over heating condition will enable the engine protection mode.