Captiva |
||||||||
|
|
|
|||||||
| • | 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 Signal | P0117 | P0118 | P0118* | P0116 |
Low Reference | - | P0118 | P0118* | P0116 |
* Sensor or ECM damage may occur if the circuit is shorted to B+ | ||||
Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
Operating Conditions: Engine operating in Closed Loop. Parameter Normal Range: -39 to 142°C (-38 to 288°F) Varies with coolant temperature. | |||
ECT Sensor Signal | 150°C (302°F) | -40°C (-40°F) | -40°C (-40°F)* |
Low Reference | - | -40°C (-40°F) | -40°C (-40°F)* |
* Internal ECM or ECT sensor damage may occur if the circuit is shorted to B+ | |||
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 V to the ECT signal circuit and supplies an ground to the low reference circuit.
The following table illustrates the difference between temperature, resistance, and voltage:
ECT | ECT Resistance | ECT Signal Voltage |
|---|---|---|
Cold | High | High |
Warm | Low | Low |
| • | The engine is operating. |
| • | The start up intake air temperature (IAT) is less than 72°C (161°F). |
OR
| • | The start up intake air temperature (IAT) is greater than 72°C (161°F). |
| • | The engine run time is greater than 59 s. |
| • | The DTC runs continuously once the above conditions are met. |
| • | The ignition is ON or the engine is operating. |
| • | The DTC runs continuously once the above condition is met. |
The ECM detects that the ECT is greater than 140°C (284°F) for greater than 1 s or a cumulative of 10 s.
The ECM detects that the ECT is less than -39°C (-38°F) for greater than 1 s or a cumulative of 10 s.
DTC P0117 and P0118 are Type B DTCs.
The ECM may activate the Cooling Fans at high speed.
DTC P0117 and P0118 are Type B DTCs.
| • | 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 DTC or a driveability condition. Refer to Temperature Versus Resistance - Engine Coolant Temperature Sensor . |
| • | If the vehicle has sat overnight, the IAT sensor and the ECT sensor values should display within 3°C (5°F). |
| • | After starting a cold engine, the ECT sensor temperature should rise steadily, then stabilise after the thermostat opens. |
| • | High resistance in the circuits of either the ECT or IAT sensor could set a DTC. |
| • | DTC's must be cleared before Engine Cooling Fan's are Commanded Off. |
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
Caution: Do NOT use a test lamp to test the continuity of the circuit. Damage to the control module may occur due to excessive current draw.
Note: The control module or the sensor may be damaged if the circuit is shorted to battery positive voltage.
| ⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance, or for a short to voltage. If the circuit tests normal, replace the K20 ECM. |
| ⇒ | If greater than the specified value, test the signal circuit terminal B for a short to ground. If the circuit tests normal, replace the K20 ECM. |
Note: If the fuse in the jumper wire opens, the signal circuit is shorted to a voltage and the sensor may be damaged.
| ⇒ | If less than the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM. |
Note: A thermometer can be used to test the sensor off the vehicle.
| ⇒ | If not within the specified range, replace the B34 ECT sensor. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Engine Coolant Temperature Sensor Replacement : LF1 or LFW |
| • | Control Module References for ECM replacement, setup, and programming |
| © Copyright Chevrolet. All rights reserved |
