Last Modified: 04-05-2023 6.11:8.1.0 Doc ID: RM100000000VIA9
Model Year Start: 2016 Model: Sienna Prod Date Range: [12/2015 - 08/2016]
Title: 2GR-FE (ENGINE CONTROL): SFI SYSTEM: P0125; Insufficient Coolant Temperature for Closed Loop Fuel Control; 2016 MY Sienna [12/2015 - 08/2016]

DTC

P0125

Insufficient Coolant Temperature for Closed Loop Fuel Control

DESCRIPTION

Refer to DTC P0115 (See page 2016 MY Sienna [12/2015 - 08/2016]; 2GR-FE (ENGINE CONTROL): SFI SYSTEM: P0115,P0117,P0118; Engine Coolant Temperature Circuit+ ).

DTC No.

DTC Detection Condition

Trouble Area

P0125

Engine coolant temperature does not reach closed loop enabling temperature for 20 minutes (this period varies with engine start engine coolant temperature)

(2 trip detection logic)
  • Cooling system
  • Engine coolant temperature sensor
  • Thermostat

MONITOR DESCRIPTION

The resistance of the engine coolant temperature sensor varies in proportion to the actual engine coolant temperature. 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 engine coolant temperature is monitored through this signal. If the engine coolant temperature 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 stores the DTC.

MONITOR STRATEGY

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

74 seconds: Engine coolant temperature at engine start is (closed-loop engine coolant temperature - 8.33°C [17°F]) or higher

137 seconds: Engine coolant temperature at engine start is (closed-loop engine coolant temperature - 19.44°C [-3°F]) or higher, and less than (closed-loop engine coolant temperature - 8.33°C [17°F])

1200 seconds: Engine coolant temperature at engine start is less than (closed-loop engine coolant temperature - 19.44°C [-3°F])

MIL Operation

2 driving cycles

Sequence of Operation

None

TYPICAL ENABLING CONDITIONS

Monitor runs whenever following DTCs are not present

None

Thermostat fail (P0128)

Not detected

Intake air temperature sensor circuit fail (P0112, P0113)

Not detected

Engine coolant temperature sensor circuit fail (P0115, P0117, P0118)

Not detected

Mass air flow meter sensor circuit fail (P0101, P0102, P0103)

Not detected

TYPICAL MALFUNCTION THRESHOLDS

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

74 seconds: Engine coolant temperature at engine start is (closed-loop engine coolant temperature - 8.33°C [17°F]) or higher

137 seconds: Engine coolant temperature at engine start is (closed-loop engine coolant temperature - 19.44°C [-3°F]) or higher, and less than (closed-loop engine coolant temperature - 8.33°C [17°F])

1200 seconds: Engine coolant temperature at engine start is less than (closed-loop engine coolant temperature - 19.44°C [-3°F])

CONFIRMATION DRIVING PATTERN

  1. Leave the vehicle outside overnight.
  2. Connect the Techstream to the DLC3.
  3. Turn the ignition switch to ON and turn the Techstream on.
  4. Enter the following menus: Powertrain / Engine / Trouble Codes.
  5. Read the DTC and record the Freeze Frame Data.
  6. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure) (See page 2016 MY Sienna [12/2015 - 08/2016]; 2GR-FE (ENGINE CONTROL): SFI SYSTEM: DTC CHECK / CLEAR ).
  7. Enter the following menus: Powertrain / Engine / Data List / Coolant Temp.
  8. Check that the Coolant Temp is the same or less than Initial Engine Coolant Temp in the freeze frame data.
  9. Turn the ignition switch off and wait for at least 30 seconds.
  10. Turn the ignition switch to ON and turn the Techstream on.
  11. Start the engine.
  12. After starting the engine, wait 20 minutes or more.
  13. Enter the following menus: Powertrain / Engine / Trouble Codes.
  14. Read pending DTCs.

    HINT:

    • If a pending DTC is output, the system is malfunctioning.
    • If a pending DTC is not output, perform the following procedure.
  15. Enter the following menus: Powertrain / Engine / Utility / All Readiness.
  16. Input the DTC: P0125.
  17. Check the DTC judgment result.

    Techstream Display

    Description

    NORMAL
    • DTC judgment completed
    • System normal

    ABNORMAL
    • DTC judgment completed
    • System abnormal

    INCOMPLETE
    • DTC judgment not completed
    • Perform driving pattern after confirming DTC enabling conditions

    N/A
    • Unable to perform DTC judgment
    • Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit
  18. If the test result is INCOMPLETE or N/A and no pending DTC is output, perform a universal trip and check for permanent DTCs (See page 2016 MY Sienna [12/2015 - 08/2016]; 2GR-FE (ENGINE CONTROL): SFI SYSTEM: DTC CHECK / CLEAR ).

    HINT:

    • If a permanent DTC is output, the system is malfunctioning.
    • If no permanent DTC is output, the system is normal.

WIRING DIAGRAM

Refer to DTC P0115 (See page 2016 MY Sienna [12/2015 - 08/2016]; 2GR-FE (ENGINE CONTROL): SFI SYSTEM: P0115,P0117,P0118; Engine Coolant Temperature Circuit+ ).

CAUTION / NOTICE / HINT

HINT:

  • If any of DTCs P0115, P0116, P0117 or P0118 are stored simultaneously with DTC P0125, the engine coolant temperature sensor may have an open or a short circuit. Troubleshoot those DTCs first.
  • Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. 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 P0125)

(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 DTCs.

Result

Result

Proceed to

DTC P0125 is output

A

DTC P0125 and other DTCs are output

B

HINT:

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

B

GO TO DTC CHART

A

2.

INSPECT THERMOSTAT

(a) Inspect the thermostat (thermostat opening temperature) (See page 2016 MY Sienna [12/2015 - 08/2016]; 2GR-FE COOLING: THERMOSTAT: INSPECTION ).

NG

REPLACE THERMOSTAT

OK

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.

HINT:

Perform "Inspection After Repair" after replacing the engine coolant temperature sensor (See page 2016 MY Sienna [12/2015 - 08/2016]; 2GR-FE (ENGINE CONTROL): SFI SYSTEM: INITIALIZATION ).

OK

REPLACE ENGINE COOLANT TEMPERATURE SENSOR

NG

REPAIR OR REPLACE COOLING SYSTEM