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Toyota Sienna Service Manual: Insufficient Coolant Temperature for Closed Loop Fuel Control

Toyota Sienna Service Manual / Engine / 2Gr-fe engine control system / Sfi system / Diagnostic trouble code chart / Insufficient Coolant Temperature for Closed Loop Fuel Control

Insufficient Coolant Temperature for Closed Loop Fuel Control

DESCRIPTION

Refer to DTC P0115 (See page ES-133).

Insufficient Coolant Temperature for Closed Loop Fuel Control

MONITOR DESCRIPTION

The resistance of the ECT sensor varies in proportion to the actual ECT. The ECM supplies a constant voltage to the sensor and monitors the signal output voltage of the sensor. The signal voltage output varies according to the changing resistance of the sensor. After the engine is started, the ECT is monitored through this signal. If the ECT sensor indicates that the engine is not yet warm enough for closed-loop fuel control, despite a specified period of time having elapsed since the engine was started, the ECM interprets this as a malfunction in the sensor or cooling system and sets the DTC.

Example: The ECT is 0°C (32°F) at engine start. After 5 minutes running time, the ECT sensor still indicates that the engine is not warm enough to begin closed-loop fuel (air-fuel ratio feedback) control. The ECM interprets this as a malfunction in the sensor or cooling system and sets the DTC.

MONITOR STRATEGY

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

TYPICAL MALFUNCTION THRESHOLDS

WIRING DIAGRAM

Refer to DTC P0115 (See page ES-134).

INSPECTION PROCEDURE

HINT

1 CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0125)

(a) Connect the intelligent tester to the DLC3.

(b) Turn the ignition switch to the ON position.

(c) Turn the tester on.

(d) Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.

(e) Read the DTCs.

Result

HINT:

If any DTCs other than P0125 are output, troubleshoot those DTCs first.

2 INSPECT THERMOSTAT

(a) Remove the thermostat (See page CO-16).

(b) Check the valve opening temperature of the thermostat (See page CO-17).

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 (See page CO-17).

3 CHECK COOLING SYSTEM

(a) Check for defects in the cooling system that might cause the system to be too cold, such as abnormal radiator fan operation or any modifications.

REPLACE ENGINE COOLANT TEMPERATURE SENSOR (See page ES-516)

Throttle / Pedal Position Sensor / Switch "A" Circuit Range / Performance Problem
HINT: This DTC relates to the Throttle Position (TP) sensor. DESCRIPTION Refer to DTC P0120 (See page ES-145). MONITOR DESCRIPTION The ECM uses the TP sensor to monitor the throttle valve ...

Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)
HINT: This DTC relates to the thermostat. DESCRIPTION This DTC is set when the Engine Coolant Temperature (ECT) does not reach 75°C (167°F) despite sufficient engine warm-up time. MON ...

Other materials:

Operation flow
HINT: Perform troubleshooting in accordance with the procedures below. The following is an outline of basic troubleshooting procedures. Confirm the troubleshooting procedures for the circuit you are working on before beginning troubleshooting. VEHICLE BROUGHT TO WORKSHOP CUSTOMER PR ...

Brake Switch
DESCRIPTION The stop light switch is a duplex system that transmits two signals: STP and ST1-. These two signals are used by the ECM to monitor whether or not the brake system is working properly. If the signals, which indicate the brake pedal is being depressed or released, are detected ...

Child restraint systems with a top tether strap (second seat)
Secure the child restraint system using the seat belt or LATCH anchors, and adjust the head restraint to the uppermost position. *: Ottoman seat only Latch the hook onto the anchor bracket and tighten the top tether strap. Make sure the top tether strap is secure ...

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