Engine Controls For California

DTC P0117, P0118 ECT SENSOR

Component Description






The engine coolant temperature sensor is used to detect the engine coolant temperature. The sensor modifies a voltage signal from the
ECM. The modified signal returns to the ECM as the engine coolant temperature input. The sensor uses a thermistor which is sensitive to the change in temperature. The electrical resistance of the thermistor decreases as temperature increases.












CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in damage to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.


On Board Diagnosis Logic

These self-diagnoses have the one trip detection logic.






FAIL-SAFE MODE

When the malfunction is detected, the ECM enters fail-safe mode and the MIL lights up.







DTC Confirmation Procedure

NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at least 10 seconds before conducting the next test.
1.Turn ignition switch ON and wait at least 5 seconds.
2.Check DTC.
3.If DTC is detected, go to .


Wiring Diagram








Diagnosis Procedure


1. CHECK GROUND CONNECTIONS

1.Turn ignition switch OFF.





2.Loosen and retighten ground screws on the body.
For California.
-White arrow indicates : Vehicle front
-Body ground (1)
OK or NG
OK- GO TO 2.
NG- Repair or replace ground connections.

2. CHECK ECT SENSOR POWER SUPPLY CIRCUIT






1.Disconnect engine coolant temperature (ECT) sensor (1) harness connector.
-White arrow indicates : Vehicle front
2.Turn ignition switch ON.





3.Check voltage between ECT sensor terminal 1 and ground with
CONSULT or tester.
Voltage: Approximately 5 V
OK or NG
OK- GO TO 3.
NG- Repair open circuit or short to ground or short to power in harness or connectors.

3. CHECK ECT SENSOR GROUND CIRCUIT FOR OPEN AND SHORT

1.Turn ignition switch OFF.
2.Disconnect ECM harness connector.
3.Check harness continuity between ECM terminal 44 and ECT sensor terminal 2.
Refer to Wiring Diagram.
Continuity should exist.
4.Also check harness for short to ground and short to power.
OK or NG
OK- GO TO 4.
NG- Repair open circuit or short to ground or short to power in harness or connectors.

4. CHECK ENGINE COOLANT TEMPERATURE SENSOR

.
OK or NG
OK- GO TO 5.
NG- Replace engine coolant temperature sensor.

5. CHECK INTERMITTENT INCIDENT

Refer to Initial Inspection and Diagnostic Overview
-INSPECTION END


Component Inspection


ENGINE COOLANT TEMPERATURE SENSOR






1.Check resistance between engine coolant temperature sensor terminals 1 and 2 as shown in the figure.










2.If NG, replace engine coolant temperature sensor.