Engine Control System - SFI System (from 12/2010)

2GR-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0115, P0117, P0118: Engine Coolant Temperature Circuit Malfunction


DESCRIPTION

A thermistor, whose resistance value varies according to the engine coolant temperature, is built into the engine coolant temperature sensor.

The structure of the sensor and its connection to the ECM are similar to those of the intake air temperature sensor.

HINT
When any of DTCs P0115, P0117 or P0118 are set, the ECM enters fail-safe mode. During fail-safe mode, the engine coolant temperature is estimated to be 80°C (176°F) by the ECM. Fail-safe mode continues until a pass condition is detected.





HINT
When any of these DTCs are set, check the engine coolant temperature by entering the following menus on the Techstream: Powertrain / Engine / Data List / All Data / Coolant Temp.





MONITOR DESCRIPTION

- The Engine Coolant Temperature (ECT) sensor is used to monitor the ECT. The ECT sensor has a thermistor with a resistance that varies according to the temperature of the engine coolant. When the coolant temperature drops, the resistance in the thermistor increases. When the temperature rises, the resistance drops. These variations in resistance are reflected in the output voltage from the sensor. The ECM monitors the sensor voltage and uses this value to calculate the ECT. When the sensor output voltage deviates from the normal operating range, the ECM interprets this as a fault in the ECT sensor and sets a DTC.

- Example:

- If the sensor output voltage is more than 4.91 V for 0.5 seconds or more, the ECM determines that there is an open in the ECT sensor circuit, and sets DTC P0118. Conversely, if the voltage output is less than 0.14 V for 0.5 seconds or more, the ECM determines that there is a short in the sensor circuit, and sets DTC P0117.

- If the malfunction is not repaired successfully, a DTC is set 0.5 seconds after the engine is next started.

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS

P0115:





P0117:





P0118:





COMPONENT OPERATING RANGE





CONFIRMATION DRIVING PATTERN





1. Connect the Techstream to the DLC3.

2. Turn the ignition switch to ON and turn the Techstream on.

3. Clear the DTCs (even if no DTCs are stored, perform the Clear DTC procedure) DTC Check / Clear (from 12/2010).

4. Turn the ignition switch off and wait for at least 30 seconds.

5. Turn the ignition switch to ON and turn the Techstream on.

6. Wait 0.5 seconds or more [A].

7. Enter the following menus: Powertrain / Engine / Utility / All Readiness.

8. Input the DTC: P0115, P0117 or P0118.

9. Check the DTC judgment result [B].





HINT
If the judgment result shows ABNORMAL, the system has a malfunction.

10. If the test result is UNKNOWN, enter the following menus: Powertrain / Engine / Trouble Codes / Pending.

11. Read Pending DTCs.

HINT
If a pending DTC is output, the system is malfunctioning.

12. If the test result is INCOMPLETE or UNKNOWN and no pending DTC is output, perform a universal trip and check for permanent DTCs DTC Check / Clear (from 12/2010).

HINT
* If a permanent DTC is output, the system is malfunctioning.
* If no permanent DTC is output, the system is normal.

WIRING DIAGRAM





INSPECTION PROCEDURE

HINT
Read freeze frame data using Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction Freeze Frame Data.

PROCEDURE

1. READ VALUE USING TECHSTREAM (COOLANT TEMP)

(a) Connect Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Data List / All Data / Coolant Temp.

(e) Read the value displayed on the Techstream.

Standard:

Between 80°C and 97°C (176°F and 207°F) with warm engine.

Result:





HINT
* If there is an open circuit, Techstream indicates -40°C (-40°F).
* If there is a short circuit, Techstream indicates 140°C (284°F).

C -- CHECK FOR INTERMITTENT PROBLEMS Check for Intermittent Problems

B -- CHECK ENGINE COOLANT TEMPERATURE SENSOR (CHECK FOR SHORT IN WIRE HARNESS)
A -- Continue to next step.

2. CHECK ENGINE COOLANT TEMPERATURE SENSOR (CHECK FOR OPEN IN WIRE HARNESS)

(a) Confirm good connection of the sensor.





(b) Disconnect the engine coolant temperature (ECT) sensor connector.

(c) Connect terminals 1 and 2 of the ECT sensor connector on the wire harness side.

(d) Connect Techstream to the DLC3.

(e) Turn the ignition switch to ON.

(f) Turn the Techstream on.

(g) Enter the following menus: Powertrain / Engine / Data List / All Data / Coolant Temp.

(h) Read the value displayed on the Techstream.

Standard:

140°C (284°F).

(i) Reconnect the ECT sensor connector.

OK -- REPLACE ENGINE COOLANT TEMPERATURE SENSOR
NG -- Continue to next step.

3. CHECK HARNESS AND CONNECTOR (ENGINE COOLANT TEMPERATURE SENSOR - ECM)

(a) Disconnect the ECT sensor connector.

(b) Disconnect the ECM connector.

(c) Measure the resistance between the terminals.

Standard resistance:





(d) Reconnect the ECM connector.

(e) Reconnect the ECT sensor connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE ECM Removal (from 12/2010)

4. CHECK ENGINE COOLANT TEMPERATURE SENSOR (CHECK FOR SHORT IN WIRE HARNESS)

(a) Disconnect the ECT sensor connector.





(b) Connect Techstream to the DLC3.

(c) Turn the ignition switch to ON.

(d) Turn the Techstream on.

(e) Enter the following menus: Powertrain / Engine / Data List / All Data / Coolant Temp.

(f) Read the value displayed on the Techstream.

Standard:

-40°C (-40°F)

(g) Reconnect the ECT sensor connector.

OK -- REPLACE ENGINE COOLANT TEMPERATURE SENSOR
NG -- Continue to next step.

5. CHECK HARNESS AND CONNECTOR (ENGINE COOLANT TEMPERATURE SENSOR - ECM)

(a) Disconnect the ECT sensor connector.

(b) Disconnect the ECM connector.

(c) Measure the resistance between the terminals.

Standard resistance:





(d) Reconnect the ECT sensor connector.

(e) Reconnect the ECM connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE ECM Removal (from 12/2010)