Toyota FJ Cruiser (GSJ 10, 15 series). Instruction - part 44

1GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEM

ES–131

FAIL-SAFE

When this DTC, as well as other DTCs relating to ETCS (Electronic Throttle Control System)
malfunctions, is set, the ECM enters fail-safe mode. During fail-safe mode, the ECM cuts the current to
the throttle actuator off, and the throttle valve is returned to a 6

° throttle angle by the return spring. The

ECM then adjusts the engine output by controlling the fuel injection (intermittent fuel-cut) and ignition
timing, in accordance with the accelerator pedal opening angle, to allow the vehicle to continue at a
minimal speed. If the accelerator pedal is depressed firmly and gently, the vehicle can be driven slowly.
Fail-safe mode continues until a pass condition is detected, and the ignition switch is then turned OFF.

INSPECTION PROCEDURE

HINT:
Read freeze frame data using an intelligent tester. 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.

(a) Connect an intelligent tester to the DLC3.
(b) Turn the ignition switch ON.
(c) Turn the tester ON.
(d) Enter the following menus: DIAGNOSIS / ENHANCED II

/ DTC INFO / CURRENT CODES.

(e) Read the DTC.

Result

CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0121)

Display (DTC Output)

Proceed to

P0121

P0121 and other DTCs

GO TO DTC CHART (See page

ES-57

)

REPLACE THROTTLE WITH MOTOR BODY ASSEMBLY (See page

ES-428

)

ES–132

1GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEM

DESCRIPTION

Refer to DTC P0115 (See page

ES-109

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 about 1 minute 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

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

WIRING DIAGRAM

Refer to DTC P0115 (See page

ES-110

DTC

P0125

Insufficient Coolant Temperature for Closed
Loop Fuel Control

DTC No.

DTC Detection Conditions

Trouble Areas

P0125

Engine coolant temperature (ECT) does not reach closed-
loop enabling temperature for 20 minutes (this period varies
with engine start ECT) (2 trip detection logic)

•

Cooling system

•

Engine coolant temperature sensor

•

Thermostat

Related DTCs

P0125: Insufficient engine coolant temperature for closed-loop fuel control

Required Sensors/Components (Main)

Engine coolant temperature sensor, thermostat, cooling system

Required Sensors/Components (Related)

Frequency of Operation

Once per driving cycle

Duration

61 seconds: Engine coolant temperature at engine start -3.3

°C (26°F) or more

109 seconds: Engine coolant temperature at engine start -14.5 to -3.3

°C (5.9 to

°F)

1,200 seconds: Engine coolant temperature at engine start -14.5

°C (5.9°F)

MIL Operation

2 driving cycles

Sequence of Operation

None

Monitor runs whenever following DTCs not present

P0100 - P0103 (MAF meter)
P0110 - P0113 (IAT sensor)
P0115 - P0118 (ECT sensor)

Thermostat fail

Not detected

Time until actual engine coolant temperature
reaches closed-loop fuel control enabling
temperature

61 seconds: Engine coolant temperature at engine start -3.3

°C (26°F) or more

109 seconds: Engine coolant temperature at engine start -14.5 to -3.3

°C (5.9 to 26°F)

1,200 seconds: Engine coolant temperature at engine start -14.5

°C (5.9°F)

1GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEM

ES–133

INSPECTION PROCEDURE

HINT:
•

If any of DTCs P0115, P0116, P0117 or P0118 are set simultaneously with DTC P0125, the Engine
Coolant Temperature (ECT) sensor may have an open or a short circuit. Troubleshoot those DTCs first.

•

Read freeze frame data using an intelligent tester. 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.

(a) Connect an intelligent tester to the DLC3.
(b) Turn the ignition switch ON.
(c) Turn the tester ON.
(d) Select the following menu items: DIAGNOSIS /

ENHANCED OBD II / DTC INFO / CURRENT CODES.

(e) Read DTCs.

Result

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

(a) Remove the water inlet with thermostat (See page

CO-

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

Standard:

° 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.

CO-

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