P1115

CIRCUIT DESCRIPTION
The engine coolant temperature (ECT) sensor is a variable resistor, that measures the temperature of the engine coolant. The powertrain control module (PCM) supplies 5 volts to the ECT signal circuit and a ground for the ECT low reference circuit. When the ECT is cold, the sensor resistance is high. When the ECT increases, the sensor resistance lowers. With high sensor resistance, the PCM detects a high voltage on the ECT signal circuit. With lower sensor resistance, the PCM detects a lower voltage on the ECT signal circuit. If the PCM detects an excessively high signal voltage, which is a low temperature indication, DTC P1115 sets.

CONDITIONS FOR RUNNING THE DTC
The engine run time is more than 60 seconds.

CONDITIONS FOR SETTING THE DTC
The PCM detects that the ECT sensor parameter is less than -38°C (-36°F) intermittently for a calibrated amount of time.

ACTION TAKEN WHEN THE DTC SETS
- The control module stores the DTC information into memory when the diagnostic runs and fails.
- The malfunction indicator lamp (MIL) will not illuminate.
- The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
- The driver information center, if equipped, may display a message.

CONDITIONS FOR CLEARING THE DTC
- A current DTC Last Test Failed clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
- Clear the DTC with a scan tool.

DIAGNOSTIC AIDS
- An ECT sensor or PCM which is intermittently shorted, open, or skewed is possible, but very unlikely
- An intermittent open or a short to voltage in the ECT sensor signal circuit could result in DTC P1115 setting. Refer to Intermittent Conditions. Intermittent Conditions
- Use the Temperature vs. Resistance Value table to test the coolant sensor at various temperature levels to evaluate the possibility of a skewed sensor. A skewed sensor could result in poor driveability conditions. Refer to Temperature vs Resistance.

TEST

Steps 1-6:

Steps 7-9: