Last Modified: 04-05-2023 6.11:8.1.0 Doc ID: RM100000000VIQ5
Model Year Start: 2016 Model: Sienna Prod Date Range: [12/2015 - 08/2016]
Title: MF1A (TRANSFER / 4WD / AWD): ACTIVE TORQUE CONTROL 4WD SYSTEM: C1241; Low Power Supply Voltage Malfunction; 2016 MY Sienna [12/2015 - 08/2016]

DTC

C1241

Low Power Supply Voltage Malfunction

DESCRIPTION

If a malfunction in the power source circuit occurs, or a malfunction in communication with the skid control ECU or in a speed sensor occurs, the 4WD control ECU will prohibit operations by the fail-safe function.

DTC No.

DTC Detection Condition

Trouble Area

C1241

  1. When the following continues for 10 seconds or more:
    • At a vehicle speed of 3 km/h (2 mph) or more, the IG1 terminal voltage is 9.5 V or less.
  2. When either of the following is detected:
    • With the IG1 terminal voltage 9.5 V or less, communication with the skid control ECU is impossible.
    • Vehicle speed sensor voltage is reduced for 60 seconds or more.
  3. When the following continues for 3 seconds or more:
    • The IG1 terminal voltage is 17 V or more.
  • Battery
  • ECU-IG1 No. 1 fuse
  • Wire harness and connector (IG1 circuit, GND circuit)
  • Brake control system
  • CAN communication system
  • 4WD control ECU

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

HINT:

Check the condition of each related circuit connector before troubleshooting (See page 2016 - 2020 MY Sienna [12/2015 -        ]; INTRODUCTION: HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS: ELECTRONIC CIRCUIT INSPECTION PROCEDURE ).

PROCEDURE

1.

CHECK FOR DTC (CAN COMMUNICATION SYSTEM AND BRAKE CONTROL SYSTEM)

(a) Check if CAN communication system DTCs are output (See page 2016 MY Sienna [12/2015 - 08/2016]; NETWORKING: CAN COMMUNICATION SYSTEM: DIAGNOSIS SYSTEM ).

(b) Start the engine.

(c) Drive the vehicle, accelerate to a speed of 3 km/h (2 mph) or more, and check if the speed sensor DTC (brake control system DTC) is output (See page 2016 - 2017 MY Sienna [12/2015 - 11/2017]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: DTC CHECK / CLEAR ).

Result

Result

Proceed to

Neither CAN communication system DTC nor speed sensor DTC (brake control system DTC) is output

A

CAN communication system DTC is output

B

Speed sensor DTC (brake control system DTC) is output

C

B

REPAIR CIRCUIT INDICATOR BY OUTPUT CODE (CAN COMMUNICATION SYSTEM)

C

REPAIR CIRCUIT INDICATOR BY OUTPUT CODE (BRAKE CONTROL SYSTEM)

A

2.

INSPECT BATTERY

(a) Check the battery voltage.

Standard voltage:

11 to 14 V

NG

CHECK CHARGING SYSTEM

OK

3.

CHECK HARNESS AND CONNECTOR (4WD CONTROL ECU - BATTERY)

(a) Disconnect the ECU connector.

(b) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

K1-11 (IG1) - Body Ground

Ignition switch ON

11 to 14 V

Text in Illustration

*a

Rear view of wire harness connector

(to 4WD Control ECU)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

4.

CHECK HARNESS AND CONNECTOR (4WD CONTROL ECU - BODY GROUND)

(a) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

K1-23 (GND) - Body Ground

Always

Below 1 Ω

Text in Illustration

*a

Rear view of wire harness connector

(to 4WD Control ECU)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

5.

RECONFIRM DTC

(a) Clear the DTC (See page 2016 - 2017 MY Sienna [12/2015 - 11/2017]; MF1A (TRANSFER / 4WD / AWD): ACTIVE TORQUE CONTROL 4WD SYSTEM: DTC CHECK / CLEAR ).

(b) Start the engine.

(c) Drive the vehicle, accelerate to a speed of 3 km/h (2 mph or more, and check if the same DTC is output.

Result

Result

Proceed to

DTC is output

A

DTC is not output

B

HINT:

Reinstall the sensor, connectors, etc. and restore the vehicle to its prior condition before rechecking DTCs.

A

REPLACE 4WD CONTROL ECU

B

CHECK FOR INTERMITTENT PROBLEMS