• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
ECT Sensor 1 Signal | P0117, P011A | P0118, P011A | P0118, P011A | P0116, P0128, P011A |
Low Reference | -- | P0118, P011A | P0118, P011A | P0128, P011A |
ECT Sensor 2 Signal | P2185 | P2184 | P2184 | P0116, P0128, P011A |
Low Reference | -- | P2184 | P2184 | P0128, P011A |
Circuit | Short to Ground | Open | Short to Voltage |
---|---|---|---|
Parameter Normal Range: -39 to +120°C (-38 to +248°F) | |||
ECT Sensor Signal | 149°C (302°F) | -40°C (-40°F) | -40°C (-40°F) |
Low Reference | -- | -40°C (-40°F) | -40°C (-40°F) |
Circuit | Short to Ground | Open | Short to Voltage |
---|---|---|---|
Parameter Normal Range: -39 to +120°C (-38 to +248°F) | |||
ECT Sensor 2 Signal | 149°C (300°F) | -40°C (-40°F) | -40°C (-40°F) |
Low Reference | -- | -40°C (-40°F) | -40°C (-40°F) |
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 signal circuit and a ground for the low reference circuit. The ECM uses this rationality diagnostic to determine if the input from the ECT sensor 1 or ECT sensor 2 is skewed. The ECM will compare the temperature difference between the ECT sensor 1 and the ECT sensor 2 to determine if the temperatures are within an acceptable operating range of each other.
• | DTCs P0117, P0118, P0128, P2184, P2105 are not set. |
• | The ignition is ON. |
• | DTC P011A runs continuously within the enabling conditions. |
When the ECM detects a temperature difference between ECT sensor 1 and ECT sensor 2 of more than 5°C (41°F).
DTC P011A is a Type B DTC.
DTC P011A is a Type B DTC.
• | Inspect the ECT sensor terminals for corrosion and for engine coolant leaking through the sensor. Engine coolant that is leaking through the sensor will create a high resistance short to ground. This condition results in less voltage on the ECT sensor signal circuit, which is interpreted by the ECM as a warmer ECT. |
• | This diagnostic runs in a specific range. Measure and record the resistance of the ECT sensor at various ambient temperatures warmer than -8°C (+18°C), then compare those measurements to the Temperature vs Resistance table. Refer to Temperature Versus Resistance . |
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
⇒ | If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle . |
Important: If you are unable to determine which ECT sensor is skewed, you must perform Circuit/System Verification first.
⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM. |
⇒ | If greater than the specified range, test the signal circuit terminal B for a short to ground. If the circuit tests normal, replace the ECM. |
⇒ | If less than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM. |
Measure and record the resistance of the ECT sensor at various ambient temperatures and compare those measurements to the Temperature vs. Resistance table. Refer to Temperature Versus Resistance .
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for ECM replacement, setup, and programming |