Toyota Tacoma manuals

Toyota Tacoma 2015-2018 Service Manual: IG Supply Voltage Low (C120B)

DESCRIPTION

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

C120B

IG Supply Voltage Low

Master cylinder pressure sensor power supply voltage decrease occurs or history of voltage decrease exists, and defective master cylinder pressure sensor output continues for 1 second or more.

  • Master cylinder pressure sensor output defective
  • Skid control ECU (Brake actuator assembly)
  • ABS NO. 2 fuse

WIRING DIAGRAM

Refer to DTC C1417 (See page 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 procedure.

PROCEDURE

1.

CHECK HARNESS AND CONNECTOR (+BS TERMINAL)

(a) Make sure that there is no looseness at the locking part and the connecting part of the connector.

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

(c) 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

S1-38 (+BS) - S1-25 (GND1)

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

2.

RECONFIRM DTC

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

(b) Clear the DTCs (See page ). (c) Check if the same DTC is recorded (See page ).

(c) Check if the same DTC is recorded (See page Result Result ).

Result

Result

Proceed to

DTC C120B is not output.

A

DTC C120B is output.

B

A

USE SIMULATION METHOD TO CHECK

B

REPLACE BRAKE ACTUATOR ASSEMBLY

Control Module Communication Bus OFF (U0073,U0100,U0124,U0126)
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Zero Point Calibration of Yaw Rate Sensor Undone (C1210,C1336)
DESCRIPTION The skid control ECU (brake actuator assembly) receives signals from the yaw rate and acceleration sensor (airbag sensor assembly) via the CAN communication system. The airbag sensor ...

Other materials:

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Removal
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Headlight Relay
Inspection INSPECTION PROCEDURE 1. INSPECT HEADLIGHT RELAY (a) Check the resistance. (1) Using an ohmmeter, measure the resistance between the terminals. Standard: Tester Connection Specified Condition 3-5 10 kΩ or higher ...

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