- When cold engine started and engine warmed up, Engine Coolant Temperature (ECT) sensor value does not change.
- After warmed up engine stopped and then next cold engine start performed, ECT sensor value does not change.
| Last Modified: 11-29-2007 | 1.6 C | |
| Service Category: Engine/Hybrid System | Section: Engine Control | |
| Model Year: 2008 | Model: Sequoia | Doc ID: RM000000PFB067X |
| Title: 2UZ-FE ENGINE CONTROL: SFI SYSTEM: DESCRIPTION (2008 Sequoia) | ||
|
DTC |
P0116 |
Engine Coolant Temperature Circuit Range / Performance Problem |
DESCRIPTION
Refer to DTC P0115
.
|
DTC No. |
DTC Detection Condition |
Trouble Area |
|---|---|---|
|
P0116 |
When either of following conditions met (2 trip detection logic): |
|
|
P0116 |
For Mexico Models: Case 1: Engine Coolant Temperature (ECT) between 35°C and 60°C (95°F and 140°F) when engine started, and conditions (a) and (b) met (2 trip detection logic)
(a) Vehicle driven at varying speeds (accelerated and decelerated) (b) ECT remains within 3°C (5.4°F) of initial ECT Case 2: ECT more than 60°C (140°F) when engine started, and conditions (a) and (b) met (6 trip detection logic)
(a) Vehicle driven at varying speeds (accelerated and decelerated) (b) ECT measurements remain within 1°C (1.8°F) of initial ECT on 6 successive occasions |
|
MONITOR DESCRIPTION
Engine coolant temperature (ECT) sensor cold start monitor
The monitor runs when the engine is started cold. If the change in engine coolant temperature sensor output until the engine warmed up completely is less than the threshold, it is determined that a malfunction has occurred in the engine coolant temperature sensor. When this is detected in 2 consecutive driving cycles, the MIL is illuminated and the DTC is stored.
ECT sensor soak monitor
The ECM compares the engine coolant temperature when the warmed engine is stopped and when the engine is started on the next trip when more than 5 hours has elapsed since the engine was stopped. If the change in engine coolant temperature sensor output is less than the threshold, it is determined that a malfunction has occurred in the engine coolant temperature sensor. When this is detected in 2 consecutive driving cycles, the MIL is illuminated and the DTC is stored.
ECT sensor high side stuck monitor (only for Mexico models)
The ECM monitors the sensor voltage and uses this value to calculate the ECT. If the sensor voltage output deviates from the normal operating range, the ECM interprets this deviation as a malfunction in the ECT sensor and stores the DTC.
Examples:
- Upon starting the engine, the ECT is between 35°C and 60°C (95°F and 140°F). If after driving for 250 seconds, the ECT remains within 3°C (5.4°F) of the starting temperature, the DTC is set (2 trip detection logic).
- Upon starting the engine, the ECT is over 60°C (140°F). If after driving for 250 seconds, the ECM remains within 1°C (1.8°F) of the starting temperature, the DTC is stored (6 trip detection logic).
MONITOR STRATEGY
|
Related DTCs |
P0116: ECT sensor cold start monitor P0116: ECT sensor soak monitor |
|
Required Sensors/Components (Main) |
ECT sensor |
|
Required Sensors/Components (Related) |
Intake Air Temperature (IAT) sensor and Mass Air Flow (MAF) meter |
|
Frequency of Operation |
Once per driving cycle |
|
Duration |
10 seconds |
|
MIL Operation |
2 driving cycles |
|
Sequence of Operation |
None |
TYPICAL ENABLING CONDITIONS
ECT Sensor Cold Start Monitor
|
Monitor runs whenever following DTCs not present |
P0102 to P0103: MAF meter P0110 to P0113: IAT sensor |
|
Battery voltage |
10.5 V or more |
|
Time after engine start |
1 second or more |
|
ECT at engine start |
Less than 60°C (140°F) |
|
IAT sensor circuit |
OK |
|
Soak time |
0 seconds or more |
|
Accumulated MAF |
2498 g or more |
|
Engine |
Running |
|
Fuel cut |
OFF |
|
Difference between ECT at engine start and IAT |
Less than 40°C (72°F) |
ECT Sensor Soak Monitor
|
Monitor runs whenever following DTCs not present |
P0102 to P0103: MAF meter P0110 to P0113: IAT sensor |
|
Battery voltage |
10.5 V or more |
|
Engine |
Running |
|
Soak time |
5 hours or more |
|
Either (a) or (b) condition met |
- |
|
(a) ECT |
60°C (140°F) or more |
|
(b) Accumulated MAF |
4942 g or more |
TYPICAL MALFUNCTION THRESHOLDS
ECT Sensor Cold Start Monitor
|
ECT sensor value change |
Less than 5°C (9°F) |
ECT Sensor Soak Monitor
|
Difference between current ECT sensor value and previous ECT sensor value when engine stopped |
Less than 5°C (9°F) |
COMPONENT OPERATING RANGE
|
ECT |
ECT sensor value changes in accordance with actual ECT |
INSPECTION PROCEDURE
HINT:
- If any of DTCs P0115, P0117, P0118 or P0125 are stored simultaneously with DTC P0116, the ECT sensor may have an open or a short circuit. Troubleshoot those DTCs first.
- Read freeze frame data using the Techstream. 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.
PROCEDURE
|
1. |
CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0116) |
(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 / Trouble Codes.
(e) Read the DTC.
Result
|
Result |
Proceed to |
|---|---|
|
P0116 |
A |
|
P0116 and other DTCs |
B |
|
|
2. |
INSPECT THERMOSTAT |
(a) Remove the thermostat
.
(b) Measure the valve opening temperature of the thermostat.
Standard:
80°C to 84°C (176°F to 183°F)
HINT:
In addition to the above check, confirm that the valve is completely closed when the temperature is below the standard.
(c) Reinstall the thermostat
.
|
|
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