3UR-FE ENGINE CONTROL: SFI SYSTEM: DESCRIPTION (2008 LX570)

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Last Modified: 11-27-2007		1.6 C
Service Category: Engine/Hybrid System	Section: Engine Control
Model Year: 2008	Model: LX570	Doc ID: RM000000PFB061X
Title: 3UR-FE ENGINE CONTROL: SFI SYSTEM: DESCRIPTION (2008 LX570)

DTC

P0116

Engine Coolant Temperature Circuit Range / Performance Problem

DESCRIPTION

Refer to DTC P0115 .

DTC Code	DTC Detection Condition	Trouble Area
P0116	When either of the following conditions is met (2 trip detection logic): When a cold engine is started and the engine is warmed up, the Engine Coolant Temperature (ECT) sensor value does not change. After the warmed up engine is stopped and then the next cold engine start is performed, the ECT sensor value does not change.	Water inlet sub-assembly with thermostat ECT sensor

MONITOR DESCRIPTION

Engine coolant temperature (ECT) sensor cold start monitor

When a cold engine start is performed and then the engine is warmed up, if the ECT sensor value does not change, it is determined that a malfunction has occurred. If this is detected in 2 consecutive driving cycles, the MIL is illuminated and a DTC is stored.

ECT sensor soak monitor

If the ECT sensor value does not change after the warmed up engine is stopped and then the next cold engine start is performed, it is determined that a malfunction has occurred. If this is detected in 2 consecutive driving cycles, the MIL is illuminated and a DTC is stored.

MONITOR STRATEGY

Related DTCs	P0116: Engine coolant temperature (ECT) sensor cold start monitor P0116: ECT sensor soak monitor
Required Sensors/Components (Main)	ECT sensor
Required Sensors/Components (Related)	None
Frequency of Operation	Once per driving cycle
Duration	10 seconds or more
MIL Operation	2 driving cycles
Sequence of Operation	None

TYPICAL ENABLING CONDITIONS

ECT sensor cold start monitor:

Monitor runs whenever following DTCs not stored	P0102 - P0103: Mass Air Flow (MAF) meter P0110 - P0113: Intake Air Temperature (IAT) sensor
Battery voltage	10.5 V or higher
Time after engine start	1 second or more
ECT at engine start	Below 60°C (140°F)
IAT sensor circuit	OK
Soak time	0 seconds or more
Accumulated MAF	1,968 g or more
Fuel cut	OFF
Difference between ECT at engine start and IAT	Below 40°C (72°F)

ECT sensor soak monitor:

Monitor runs whenever following DTCs not stored	P0102 - P0103: MAF meter
Battery voltage	10.5 V or higher
Engine	Running
Soak time	5 hours or more
Either (a) or (b) condition met	-
(a) ECT	60°C (140°F) or higher
(b) Accumulated MAF	4,165 g or more

TYPICAL MALFUNCTION THRESHOLDS

ECT sensor cold start monitor:

ECT sensor value change

Below 5°C (9°F)

ECT sensor soak monitor:

Difference between current ECT sensor value and previous ECT sensor value when engine stopped

Below 3°C (5.4°F) [varies with ECT of last trip engine stop]

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 is output 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 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.	CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0116)

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(d) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

(e) Read the DTC.

Result

Result	Proceed to
P0116 is output	A
P0116 and other DTCs are output	B

2.	INSPECT WATER INLET SUB-ASSEMBLY WITH THERMOSTAT

(a) Remove the water inlet sub-assembly with thermostat .

(b) Measure the valve opening temperature of the water inlet sub-assembly with thermostat.

Standard opening temperature:

80 to 84°C (176 to 183°F)

HINT:

In addition to the above check, confirm that the valve is completely closed when the temperature is below the standard.