DTC 22 Engine Coolant Temperature Sensor Circuit Malfunction
DESCRIPTION
The engine coolant temperature sensor senses the coolant temperature. A thermistor built into the sensor changes its resistance according to the coolant temperature. The lower the coolant temperature, the higher the thermistor resistance value, and the higher the coolant temperature, the lower the thermistor resistance value (see Fig. 1).
The engine coolant temperature sensor is connected to the ECM. The 5 V power source voltage from the ECM is applied to the engine coolant temperature sensor from terminal THW via resistor R. That is, resistor R and the engine coolant temperature sensor are connected in series. When the resistance value of the engine coolant temperature sensor changes in accordance with changes in the coolant temperature, the voltage at terminal THW also changes. Based on this signal, the ECM increases the fuel injection volume to improve driveability during cold engine operation.
| DTC No. | DTC Detection Condition | Trouble Area |
| 22 | Open or short in the engine coolant temperature sensor circuit for 0.5 sec. or more. | Open or short in engine coolant temperature sensor circuit
Engine coolant temperature sensor
ECM
|
WIRING DIAGRAM
INSPECTION PROCEDURE
If DTCs related to different systems that have terminal E2 as the ground terminal are stored simultaneously, there may be an open circuit between terminal E2 and body ground.
Read freeze frame data using the intelligent tester. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, and other data from the time the malfunction occurred.
When using intelligent tester:
| 1.READ VALUE USING INTELLIGENT TESTER (ENGINE COOLANT TEMPERATURE) |
Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.
Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
Result| Result | Proceed to |
| -40°C (-40°F) | A |
| 140°C (284°F) or higher | B |
| Value is same as actual engine coolant temperature | C |
- When DTC 22 is stored, the type of malfunction can be determined based on the engine coolant temperature (see below).
| Temperature Displayed | Malfunction |
| -40°C (-40°F) | Open circuit |
| 140°C (284°F) or higher | Short circuit |
| |
|
| | CHECK FOR INTERMITTENT PROBLEMS
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| 2.READ VALUE USING INTELLIGENT TESTER (CHECK FOR OPEN IN WIRE HARNESS) |
Disconnect the engine coolant temperature sensor connector.
Connect terminals 1 and 2 of the engine coolant temperature sensor harness side connector.
Turn the ignition switch to ON.
Read the temperature value on the intelligent tester.
- OK:
- 140°C (284°F) or higher
Text in Illustration| *1 | Engine Coolant Temperature Sensor |
| *2 | ECM |
| *a | Front view of wire harness connector
(to Engine Coolant Temperature Sensor) |
Reconnect the engine coolant temperature sensor connector.
| OK | |
| |
| REPLACE ENGINE COOLANT TEMPERATURE SENSOR
|
|
| 3.READ VALUE USING INTELLIGENT TESTER (CHECK FOR OPEN IN ECM) |
Connect terminals THW and E2 of the ECM connector.
Turn the ignition switch to ON.
Read the temperature value on the intelligent tester.
- OK:
- 140°C (284°F) or higher
Text in Illustration| *1 | Engine Coolant Temperature Sensor |
| *2 | ECM |
| *a | Component with harness connected
(ECM) |
| OK | |
| |
| REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 4.READ VALUE USING INTELLIGENT TESTER (CHECK FOR SHORT IN WIRE HARNESS) |
Disconnect the engine coolant temperature sensor connector.
Turn the ignition switch to ON.
Read the temperature value on the intelligent tester.
Text in Illustration| *1 | Engine Coolant Temperature Sensor |
| *2 | ECM |
Reconnect the engine coolant temperature sensor connector.
| OK | |
| |
| REPLACE ENGINE COOLANT TEMPERATURE SENSOR
|
|
| 5.READ VALUE USING INTELLIGENT TESTER (CHECK FOR SHORT IN ECM) |
Disconnect the ECM connector.
Turn the ignition switch to ON.
Read the temperature value on the intelligent tester.
Text in Illustration| *1 | Engine Coolant Temperature Sensor |
| *2 | ECM |
| *a | Rear view of wire harness connector
(to ECM) |
Reconnect the ECM connector.
| OK | |
| |
| REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
When not using intelligent tester:
| 1.CHECK ECM (THW VOLTAGE) |
Turn the ignition switch to ON.
Measure the voltage according to the value(s) in the table below.
- Standard Voltage:
| Tester Connection | Condition | Specified Condition |
| C102-4 (THW) - C102-9 (E2) | 20°C (68°F) | 0.2 to 3.8 V |
| C102-4 (THW) - C102-9 (E2) | 80°C (176°F) | 0.1 to 1.5 V |
Text in Illustration| *a | Component with harness connected
(ECM) |
| OK | |
| |
| CHECK FOR INTERMITTENT PROBLEMS
|
|
| 2.INSPECT ENGINE COOLANT TEMPERATURE SENSOR |
Inspect the engine coolant temperature sensor (See page ).
| | REPLACE ENGINE COOLANT TEMPERATURE SENSOR
|
|
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| 3.CHECK HARNESS AND CONNECTOR (ECM - ENGINE COOLANT TEMPERATURE SENSOR) |
Disconnect the engine coolant temperature sensor connector.
Disconnect the ECM connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance (Check for Open):
| Tester Connection | Condition | Specified Condition |
| C111-2 - C102-4 (THW) | Always | Below 1 Ω |
| C111-1 - C102-9 (E2) | Always | Below 1 Ω |
- Standard Resistance (Check for Short):
| Tester Connection | Condition | Specified Condition |
| C111-2 or C102-4 (THW) - Body ground | Always | 10 kΩ or higher |
Reconnect the engine coolant temperature sensor connector.
Reconnect the ECM connector.
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
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