- Open or short in ECT sensor circuit
- ECT sensor
- ECM
| Last Modified: 11-29-2007 | 1.6 C | |
| Service Category: Engine/Hybrid System | Section: Engine Control | |
| Model Year: 2008 | Model: Sequoia | Doc ID: RM000000PF505MX |
| Title: 3UR-FE ENGINE CONTROL: SFI SYSTEM: DESCRIPTION (2008 Sequoia) | ||
|
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, whose resistance value varies according to the ECT, is built into the Engine Coolant Temperature (ECT) sensor.
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 stored, 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. |
DTC Detection Condition |
Trouble Area |
|---|---|---|
|
P0115 |
Open or short in ECT sensor circuit for 0.5 seconds (1 trip detection logic) |
|
|
P0117 |
Short in ECT sensor circuit for 0.5 seconds (1 trip detection logic) |
|
|
P0118 |
Open in ECT sensor circuit for 0.5 seconds (1 trip detection logic) |
|
HINT:
When any of these DTCs are stored, check the ECT by entering the following menus: Powertrain / Engine and ECT / Data List / All Data / Coolant Temp.
|
Temperature Displayed |
Malfunction |
|---|---|
|
-40°C (-40°F) |
Open circuit |
|
140°C (284°F) or higher |
Short circuit |
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 is low, the resistance in the thermistor increases. When the temperature is high, 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 stores 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 stores 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 stores DTC P0117.
If the malfunction is not repaired successfully, a DTC is stored 0.5 seconds after the engine is next started.
MONITOR STRATEGY
|
Related DTCs |
P0115: ECT sensor range check (Fluctuating) P0117: ECT sensor range check (Low voltage) P0118: ECT sensor range check (High voltage) |
|
Required Sensors/Components (Main) |
ECT sensor |
|
Required Sensors/Components (Related) |
- |
|
Frequency of Operation |
Continuous |
|
Duration |
0.5 seconds |
|
MIL Operation |
Immediate |
|
Sequence of Operation |
None |
TYPICAL ENABLING CONDITIONS
|
Monitor runs whenever following DTCs not present |
None |
TYPICAL MALFUNCTION THRESHOLDS
P0115
|
ECT sensor voltage |
Less than 0.14 V, or more than 4.91 V |
P0117
|
ECT sensor voltage [ECT] |
Less than 0.14 V [More than 140°C (284°F)] |
P0118
|
ECT sensor voltage [ECT] |
More than 4.91 V [Less than -40°C (-40°F)] |
COMPONENT OPERATING RANGE
|
ECT sensor voltage [ECT] |
0.14 to 4.91 V [-40 to 140°C (-40 to 284°F)] |
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:
Read freeze frame data using the Techstream. 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, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.
PROCEDURE
|
1. |
READ OUTPUT DTC |
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the Techstream on.
(d) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
(e) Read DTCs.
Result
|
Result |
Proceed to |
|---|---|
|
P0115 is output |
A |
|
P0117 is output |
B |
|
P0118 is output |
C |
|
|
2. |
READ VALUE USING TECHSTREAM (ENGINE COOLANT TEMPERATURE) |
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the Techstream on.
(d) Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Coolant Temp.
(e) Read the value displayed on the Techstream.
Standard value:
Between 80 and 100°C (167 and 212°F) with warm engine.
Result
|
Result |
Proceed to |
|---|---|
|
-40°C (-40°F) |
A |
|
140°C (284°F) or higher |
B |
|
Between 80 and 100°C (176 and 212°F) |
C |
HINT:
- If there is an open circuit, the Techstream indicates -40°C (-40°F).
- If there is a short circuit, the Techstream indicates 140°C (284°F) or higher.
|
|
3. |
READ VALUE USING TECHSTREAM (CHECK FOR OPEN IN WIRE HARNESS) |
(a) Disconnect the ECT sensor connector.
(b) Connect terminals 1 and 2 of the ECT sensor connector on the wire harness side.
(c) Connect the Techstream to the DLC3.
(d) Turn the ignition switch to ON.
(e) Turn the Techstream on.
(f) Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Coolant Temp.
(g) Read the value displayed on the Techstream.
Standard value:
140°C (284°F) or higher
|
|
4. |
CHECK HARNESS AND CONNECTOR (ENGINE COOLANT TEMPERATURE SENSOR - ECM) |
(a) Disconnect the ECT sensor connector.
(b) Disconnect the ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
D15-2 - D56-76 (THW) |
Always |
Below 1 Ω |
|
D15-1 - D56-98 (ETHA) |
Always |
Below 1 Ω |
|
|
9. |
READ VALUE USING TECHSTREAM (CHECK FOR SHORT IN WIRE HARNESS) |
(a) Disconnect the ECT sensor connector.
(b) Connect the Techstream to the DLC3.
(c) Turn the ignition switch to ON.
(d) Turn the Techstream on.
(e) Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Coolant Temp.
(f) Read the value displayed on the Techstream.
Standard value:
-40°C (-40°F)
|
|
10. |
CHECK HARNESS AND CONNECTOR (ENGINE COOLANT TEMPERATURE SENSOR - ECM) |
(a) Disconnect the ECT sensor connector.
(b) Disconnect the ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
D15-2 or D56-76 (THW) - Body ground |
Always |
10 kΩ or higher |
|
|
|