Brand:

Toyota

Model Name:

Yaris NCP90 91 92 93

Manual:

Repair Manual

Section:

1Nz-Fe Engine Control System

Title:

Sfi System

  1. Description

  2. Wiring diagram

  3. Inspection procedure

  4. Read value using intelligent tester (engine coolant temperature)

  5. Read value using intelligent tester (check for open in wire harness)

  6. Check harness and connector (engine coolant temperature sensor - ecm)

  7. Read value using intelligent tester (check for short in wire harness)

  8. Check harness and connector (engine coolant temperature sensor - ecm)

DTC P0115 Engine Coolant Temperature Circuit Malfunction

DTC P0117 Engine Coolant Temperature Circuit Low Input

DTC P0118 Engine Coolant Temperature Circuit High Input


​

DESCRIPTION

A thermistor is built into the Engine Coolant Temperature (ECT) sensor, of which the resistance value varies according to the ECT.
The structure of the sensor and its connection to the ECM are the same as those of the Intake Air Temperature (IAT) sensor.
HINT:
When any of DTCs P0115, P0117 and P0118 are set, the ECM enters fail-safe mode. During fail-safe mode, the ECT is estimated to be 80°C (176°F) by the ECM. Fail-safe mode continues until a pass condition is detected.

DTC No.
Proceed To
DTC Detection Conditions
Trouble Areas
P0115
Step 1
Open or short in ECT sensor circuit for 0.5 seconds (1 trip detection logic)
  1. Open or short in ECT sensor circuit
  2. ECT sensor
  3. ECM
P0117
Step 4
Short in ECT sensor circuit for 0.5 seconds (1 trip detection logic)
  1. Short in ECT sensor circuit
  2. ECT sensor
  3. ECM
P0118
Step 2
Open in ECT sensor circuit for 0.5 seconds (1 trip detection logic)
  1. Open in ECT sensor circuit
  2. ECT sensor
  3. ECM
HINT:
When any of these DTCs are set, check the ECT by selecting the following menu items on an intelligent tester: Powertrain / Engine and ECT / Data List / Coolant Temp.

Temperature Displayed
Malfunctions
-40°C (-40°F)
Open circuit
140°C (284°F) or higher
Short circuit

WIRING DIAGRAM


Connect an intelligent tester to the DLC3. Yaris


INSPECTION PROCEDURE

HINT:
Read freeze frame data using an intelligent tester. Freeze frame data record 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, if the air-fuel ratio was lean or rich, and other data, from the time the malfunction occurred.
1.READ VALUE USING INTELLIGENT TESTER (ENGINE COOLANT TEMPERATURE)

  1. Connect an intelligent tester to the DLC3.

  1. Turn the ignition switch to ON and turn the tester on.

  1. Select the following menu items: Powertrain / Engine and ECT / Data List / Coolant Temp.

  1. Read the value displayed on the tester.

    Standard:
    80°C to 100°C (176°F to 212°F) with warm engine.
    Result:
    Temperature Displayed
    		Proceed To
    -40°C (-40°F)
    		A
    140°C (284°F) or higher
    		B
    80°C to 100°C (176°F to 212°F)
    		C
    HINT:
    1. If there is an open circuit, the intelligent tester indicates -40°C (-40°F).
    2. If there is a short circuit, the intelligent tester indicates 140°C (284°F) or higher.


Bnext
Go to step 4

Cnext
CHECK FOR INTERMITTENT PROBLEMS (Click here)
A
next down

2.READ VALUE USING INTELLIGENT TESTER (CHECK FOR OPEN IN WIRE HARNESS)
  1. Disconnect the C19 Engine Coolant Temperature (ECT) sensor connector. Yaris

  2. Disconnect the C19 Engine Coolant Temperature (ECT) sensor connector.

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

  1. Connect an intelligent tester to the DLC3.

  1. Turn the ignition switch to ON and turn the tester on.

  1. Select the following menu items: Powertrain / Engine and ECT / Data List / Coolant Temp.

  1. Read the value displayed on the tester.

    Standard:
    140°C (284°F) or higher.

  1. Reconnect the ECT sensor connector.



OKnext
CONFIRM GOOD CONNECTION TO SENSOR. IF OK, REPLACE ENGINE COOLANT TEMPERATURE SENSOR
NG
next down

3.CHECK HARNESS AND CONNECTOR (ENGINE COOLANT TEMPERATURE SENSOR - ECM)
  1. Disconnect the C19 ECT sensor connector. Yaris

  2. Disconnect the C19 ECT sensor connector.

  1. Disconnect the C20 ECM connector.

  1. Check the resistance.

    Standard resistance:
    Tester Connections
    		Specified Conditions
    THW (C19-2) - THW (C20-97)
    		Below 1 Ω
    E2 (C19-1) - ETHW (C20-96)

  1. Reconnect the ECT sensor connector.

  1. Reconnect the ECM connector.



NGnext
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
next down
CONFIRM GOOD CONNECTION TO ECM. IF OK, REPLACE ECM

4.READ VALUE USING INTELLIGENT TESTER (CHECK FOR SHORT IN WIRE HARNESS)
  1. Disconnect the C19 ECT sensor connector. Yaris

  2. Disconnect the C19 ECT sensor connector.

  1. Connect an intelligent tester to the DLC3.

  1. Turn the ignition switch to ON and turn the tester on.

  1. Select the following menu items: Powertrain / Engine and ECT / Data List / Coolant Temp.

  1. Read the value displayed on the tester.

    Standard:
    -40°C (-40°F)

  1. Reconnect the ECT sensor connector.



OKnext
REPLACE ENGINE COOLANT TEMPERATURE SENSOR
NG
next down

5.CHECK HARNESS AND CONNECTOR (ENGINE COOLANT TEMPERATURE SENSOR - ECM)
  1. Disconnect the C19 ECT sensor connector. Yaris

  2. Disconnect the C19 ECT sensor connector.

  1. Disconnect the C20 ECM connector.

  1. Check the resistance.

    Standard resistance:
    Tester Connections
    		Specified Conditions
    THW (C19-2) or THW (C20-97) - Body ground
    		10 kΩ or higher

  1. Reconnect the ECT sensor connector.

  1. Reconnect the ECM connector.



NGnext
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
next down
REPLACE ECM (Click here)