Last Modified: 4-30-2014 6.6 C Doc ID: RM000000YDB00BX
Model Year: 2006 Model: LX470 Prod Date Range: [05/2005 -           ]
Title: 2UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0116; Engine Coolant Temperature Circuit Range / Performance Problem; 2006 MY LX470 [05/2005 -        ]

DTC

P0116

Engine Coolant Temperature Circuit Range / Performance Problem

DESCRIPTION

Refer to DTC P0115 2006 MY LX470 [05/2005 -        ]; 2UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0115,P0117,P0118; Engine Coolant Temperature Circuit+ .

DTC No.

DTC Detection Condition

Trouble Area

P0116

  • If Engine Coolant Temperature (ECT) is 35 to 60°C (95 to 140°F) when engine is started, and if conditions (a) and (b) are met:
    • (a) Vehicle has accelerated and decelerated
    • (b) ECT remains within 3°C (5.4°F) of the initial ECT (2 trip detection logic)
  • Cooling system
  • Engine Coolant Temperature (ECT) sensor

P0116

  • If ECT is more than 60°C (140°F) when engine is started and the vehicle has accelerated and decelerated
  • If ECT sensor records an ECT variation below 1°C (1.8°F) (6 trip detection logic)
  • Cooling system
  • ECT sensor

MONITOR DESCRIPTION

The Engine Coolant Temperature (ECT) sensor is used to monitor the engine coolant temperature. The ECT sensor has a thermistor that varies its resistance depending on 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. The variations in resistance are reflected in the voltage output 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.

Examples:

  1. Upon starting the engine, the ECT is between 35°C (95°F) and 60°C (140°F). If after driving for 250 seconds, the ECT still remains within 3°C (5.4°F) of the starting temperature, a DTC will be set (2 trip detection logic).
  2. Upon starting the engine, the ECT is over 60°C (140°F). If, after driving for 250 seconds, the ECT still remains within 1°C (1.8°F) of the starting temperature, a DTC will be set (6 trip detection logic).

MONITOR STRATEGY

Related DTCs

P0116: Engine Coolant Temperature (ECT) sensor stuck (low ECT)

P0116: ECT sensor stuck (high ECT)

Required Sensors/Components (Main)

Engine Coolant Temperature sensor

Required Sensors/Components (Related)

Crankshaft position sensor, IAT sensor, MAF meter

Frequency of Operation

Once per driving cycle: ECT sensor stuck (low ECT)

Continuous: ECT sensor stuck (high ECT)

Duration

1 second

MIL Operation

2 driving cycles: ECT sensor stuck (low ECT)

6 driving cycles: ECT sensor stuck (high ECT)

Sequence of Operation

None

TYPICAL ENABLING CONDITIONS

Monitor will run whenever these DTCs are not present

P0100 - P0103 (MAF sensor)

Engine Coolant Temperature sensor stuck (low Engine Coolant Temperature):

Cumulative idle off period

250 seconds or more

Vehicle speed increase of 30 km/h (19 mph) or more

10 times or more

Engine coolant temperature

35 to 60°C (95 to 140°F)

Intake air temperature

-6.7°C (20°F) or more

Intake air temperature sensor circuit fail

Not detected

Engine Coolant Temperature sensor stuck (high Engine Coolant Temperature):

Engine coolant temperature

60°C (220°F) or more

Intake air temperature

-6.7°C (20°F) or more

"Stop and go" *1

One or more times

"Steady driving and stop" *2

One or more times

Engine running time after engine start

0.3 seconds or more

HINT:

*1: Vehicle is stopped for 20 seconds or more and accelerated to more than 70 km/h (44 mph) within 40 seconds.

*2: Follow these steps: 1) vehicle is driven at 65 km/h (40 mph) or more for 30 seconds or more and the vehicle speed reaches 70 km/h (44 mph); 2) vehicle is decelerated from 65 km/h (40 mph) to 3 km/h (2 mph) or less within 35 seconds; and 3) vehicle is stopped for 10 seconds.

TYPICAL MALFUNCTION THRESHOLDS

Engine Coolant Temperature sensor stuck (low Engine Coolant Temperature):

Engine coolant temperature change

Less than 3°C (5.4°F)

Engine Coolant Temperature sensor stuck (high Engine Coolant Temperature):

Engine coolant temperature change

1°C (1.8°F) or less

COMPONENT OPERATING RANGE

Engine coolant temperature

Varies with actual engine coolant temperature

WIRING DIAGRAM

Refer to DTC P0115 2006 MY LX470 [05/2005 -        ]; 2UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0115,P0117,P0118; Engine Coolant Temperature Circuit+ .

INSPECTION PROCEDURE

HINT:

  • If DTC P0115, P0116, P0117, P0118 and P0125 are output simultaneously, ECT sensor circuit may be open or shorted. Perform the troubleshooting of DTC P0115, P0117 or P0118 first.
  • Read freeze frame data using the intelligent tester. Freeze frame data records the engine conditions when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, 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 OTHER DTC OUTPUT (IN ADDITION TO DTC P0116)

(a) Connect the intelligent tester to the CAN VIM. Then connect the CAN VIM to the DLC3.

(b) Turn the ignition switch ON.

(c) Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.

(d) Read the DTCs.

Display (DTC output)

Proceed to

P0116

A

P0116 and other DTCs

B

B

GO TO RELEVANT DTC CHART

A

2.

INSPECT THERMOSTAT

(a) Remove the thermostat 2006 MY LX470 [05/2005 -        ]; 2UZ-FE COOLING: THERMOSTAT: REMOVAL .

(b) Check the valve opening temperature of the thermostat.

Standard:

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.

(c) Reinstall the thermostat 2006 MY LX470 [05/2005 -        ]; 2UZ-FE COOLING: THERMOSTAT: INSTALLATION .

NG

REPLACE THERMOSTAT

OK

REPLACE ENGINE COOLANT TEMPERATURE SENSOR