P1115
DTC P1115CIRCUIT DESCRIPTION
The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The engine control module (ECM) supplies 5 volts to the ECT signal circuit and supplies a ground to the low reference circuit. If the ECM detects an intermittent high ECT signal voltage, which is a low temperature indication, this DTC sets.
The table illustrates the difference between temperature, resistance, and voltage:
DTC DESCRIPTOR
This diagnostic supports the following DTC:
DTC P1115 Engine Coolant Temperature (ECT) Sensor Circuit Intermittent High Voltage
CONDITIONS FOR RUNNING THE DTC
- The engine run time is more than 120 seconds.
- This DTC runs continuously once the above condition is met.
CONDITIONS FOR SETTING THE DTC
The ECM detects that the engine coolant temperature is less than -38°C (-36°F) intermittently.
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
- Test the ECT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor can result in a driveability condition.
- If the vehicle has set overnight, the ECT sensor and the intake air temperature (IAT) sensor values should display within 3°C (5°F). Refer to Temperature vs Resistance.
- For an intermittent condition, refer to Intermittent Conditions. Intermittent Conditions
TEST
