Toyota Tacoma manuals

Toyota Tacoma 2015-2018 Service Manual: Low Power Supply Voltage Malfunction (C1241)

DESCRIPTION

If a malfunction is detected in the power supply circuit, the skid control ECU (brake actuator assembly) stores this DTC and the fail-safe function prohibits ABS operation.

This DTC is stored when the +BS terminal voltage deviates from the DTC detection condition due to a malfunction in the power supply or charging circuit such as the battery or generator circuit, etc.

The DTC is canceled when the +BS terminal voltage returns to normal.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

C1241

Low Power Supply Voltage Malfunction

Any of the following is detected:

  • When vehicle speed is 3 km/h (2 mph) or more, +BS terminal voltage is continuously below 9.5 V for 10 seconds or more.
  • When solenoid relay is on, +BS terminal voltage is below 9.5 V and relay contact is off for 0.22 seconds or more.
  • When +BS terminal voltage is below 9.5 V, power supply voltage of vehicle speed sensor is continuously low for 60 seconds or more.
  • When fail-safe motor relay is on and +BS terminal voltage is below 9.5 V, fail-safe motor relay overcurrent continues for 0.05 seconds or more.
  • ABS NO. 2 fuse
  • Battery
  • Charging system
  • Wire harness or connector
  • Skid control ECU (Brake actuator assembly)

HINT:

DTC will be output when conditions for any of the patterns in the table above are met.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

CAUTION / NOTICE / HINT

NOTICE:

  • When replacing the skid control ECU (brake actuator assembly), perform zero point calibration and store system information (See page ).
  • Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE

1.

INSPECT BATTERY

(a) Check the battery voltage.

Standard voltage:

11 to 14 V

NG

CHECK OR REPLACE CHARGING SYSTEM OR BATTERY

OK

2.

CHECK TERMINAL VOLTAGE (+BS TERMINAL)

(a) Turn the ignition switch off.

(b) Make sure that there is no looseness in the locking part and connecting part of the connectors.

(c) Disconnect the skid control ECU (brake actuator assembly) connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

S1-38 (+BS) - Body ground

Always

11 to 14 V

Text in Illustration

*a

Front view of wire harness connector

(to Skid Control ECU [Brake Actuator Assembly])

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (+BS CIRCUIT)

OK

3.

CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)

(a) Turn the ignition switch off.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

S1-25 (GND1) - Body ground

Always

Below 1 Ω

Text in Illustration

*a

Front view of wire harness connector

(to Skid Control ECU [Brake Actuator Assembly])

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (GND1 CIRCUIT)

OK

4.

RECONFIRM DTC

(a) Reconnect the S1 skid control ECU (brake actuator assembly) connector.

(b) Clear the DTC (See page ). (c) Turn the ignition switch off. ).

(c) Turn the ignition switch off.

(d) Start the engine.

(e) Drive the vehicle at a speed of 20 km/h (12 mph) or more for 30 seconds or more.

(f) Check if the same DTC is recorded (See page HINT: HINT: ).

HINT:

If troubleshooting has been carried out according to the Problem Symptoms Table, refer back to the table and proceed to the next step (See page Result Result ).

Result

Result

Proceed to

DTC C1241 is not output

A

DTC C1241 is output

B

A

USE SIMULATION METHOD TO CHECK

B

REPLACE BRAKE ACTUATOR ASSEMBLY

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