Toyota Tacoma manuals

Toyota Tacoma (2015-2018) Service Manual: Open Circuit in IG1/IG2 Power Source Circuit (C1242)

DESCRIPTION

If there is a problem with the skid control ECU (master cylinder solenoid) power supply circuit, the skid control ECU outputs the DTC and prohibits operation under the fail safe function.

If the voltage supplied to terminal IG1 and/or IG2 is not within the DTC detection threshold due to malfunctions in parts such as the battery or alternator circuit, this DTC is stored.

DTC No.

DTC Detecting Condition

Trouble Areas

C1242

Vehicle speed 3 km/h (1.9 mph) or more and voltage of skid control ECU (master cylinder solenoid) terminal IG1 and/or IG2 remains at below 6.5 V for more than 7 seconds.

  • Battery
  • IC regulator
  • Power source circuit
  • Skid control ECU (master cylinder solenoid)

WIRING DIAGRAM

CAUTION / NOTICE / HINT

CAUTION / NOTICE / HINT

NOTICE:

  • When replacing the skid control ECU (master cylinder solenoid), perform zero point calibration (See page ). Inspect the fuses for circuits related to this system before performing ).
  • 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

GO TO CHARGING SYSTEM

OK

2.

CHECK HARNESS AND CONNECTOR (IG2 TERMINAL)

(a) Disconnect the skid control ECU (master cylinder solenoid) connector.

(b) Turn the ignition switch to the ON position.

(c) Measure the voltage.

Standard Voltage:

Tester Connection

Specified Condition

S2-1 (IG2) - Body ground

10 to 14 V

Text in Illustration

*a

Front view of wire harness connector

(to Skid Control ECU (Master Cylinder Solenoid))

(d) Reconnect the skid control ECU (master cylinder solenoid) connector.

(e) Turn the ignition switch to OFF.

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

3.

CHECK HARNESS AND CONNECTOR (GND TERMINAL)

(a) Disconnect the skid control ECU (master cylinder solenoid) connectors.

(b) Measure the resistance.

Standard Resistance:

Tester Connection

Specified Condition

S1-1 (GND1) - Body ground

Below 1 Ω

S1-32 (GND2) - Body ground

Below 1 Ω

S2-4 (GND3) - Body ground

Below 1 Ω

(c) Reconnect the skid control ECU (master cylinder solenoid) connectors.

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

4.

RECONFIRM DTC

(a) Clear the DTCs (See page ). (b) Drive the vehicle at a speed of 3 km/h (1.9 mph) or more for 7 seconds or ).

(b) Drive the vehicle at a speed of 3 km/h (1.9 mph) or more for 7 seconds or more.

(c) Check if the same DTCs are detected.

Result

Proceed to

DTC output

A

DTC not output

B

A

REPLACE MASTER CYLINDER SOLENOID

B

END

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