Circuit Description
The engine coolant temperature (ECT) sensor is a thermistor mounted in the engine coolant stream. The powertrain control module (PCM) applies a voltage of about 5 volts to the ECT sensor through a pull up resistor. When the engine coolant is cold, the sensor resistance is high and the PCM measures a high signal voltage. As the engine coolant warms, the sensor resistance becomes less, and the ECT signal voltage measured at the powertrain control module (PCM) drops. With a fully warmed up engine, the ECT signal voltage should measure about 1.5 to 2.0 volts. If the PCM detects an ECT signal that is intermittently below the range of the ECT sensor, DTC P1114 is set.
Conditions for Running the DTC
The engine is running longer than 3 seconds.
Conditions for Setting the DTC
The ECT sensor intermittently indicates an ECT of less than -13°C (9°F).
Action Taken When the DTC Sets
The PCM stores the conditions which were present when the DTC set as Fail Records data only.
Conditions for Clearing the MIL/DTC
| • | A history DTC clears after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC may be cleared using the scan tool Clear Info function or by disconnecting the PCM battery feed. |
Diagnostic Aids
Inspect for the following conditions:
| • | A faulty connection at the PCM. Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connections. |
| • | Inspect the wiring harness for damage. If the harness appears to be OK, observe the ECT display on a scan tool while moving the connectors and wiring harnesses related to the ECT sensor. A change in the ECT display indicates the location of the malfunction. |
| • | A skewed or mis-scaled ECT sensor. Refer to Temperature vs Resistance . |
Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
2 | Use the scan tool in order to select DTC info, Last Tst Fail and note any other DTCs set. Is DTC P0117 also set? | -- | Go to DTC P0117 Engine Coolant Temperature (ECT) Sensor Circuit Low Voltage | |
3 |
Was a problem found? | -- | Go to Diagnostic Aids | |
4 |
Does the scan tool indicate DTC P1114 failed? | -- | System OK |
