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 131°C (268°F). 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 SETTING THE DTC

^ DTCs P0117, P0118, P0125 are not set.

^ The engine is running.

^ The engine coolant temperature is greater than 132°C (270°F).

^ The above conditions exist for more than 10 seconds.

ACTION TAKEN WHEN THE DTC SETS

^ The PCM illuminates the Malfunction Indicator Lamp on the second consecutive drive trip that the diagnostic runs and fails.

^ The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive drive trip, the PCM records the operating conditions at the time of the failure. The PCM writes the conditions to the Freeze Frame and updates the Failure records.

CONDITIONS FOR CLEARING THE MIL/DTC

^ The PCM turns the MIL OFF after three consecutive drive trips 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 forty consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures.

^ The PCM battery voltage is interrupted.

^ Use a scan tool in order to clear the MIL/DTC.

DIAGNOSTIC AIDS

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

Using the Freeze Frame and/or Failure Records data may aid in locating an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame and/or Failure Records data can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can also help determine how many ignition cycles the diagnostic reported a pass and/or a fail. Operate the vehicle within the same freeze frame conditions (RPM, load, vehicle speed, temperature etc.) that you observed. This will isolate when the DTC failed. For an intermittent condition, refer to Symptoms. Testing and Inspection


TEST DESCRIPTION

The numbers below refer to the step numbers on the diagnostic table.

2. A faulty ECT sensor, an ECT sensor circuit malfunction, or a cooling system problem will enable the engine protection mode.