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

Toyota Tacoma (2015-2018) Service Manual / Brake Control / Dynamic Control Systems / Vehicle Stability Control System(for Hydraulic Brake Booster) / Low Power Supply Voltage Malfunction (C1241)

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 is not within the DTC detection threshold due to malfunctions in parts such as the battery and generator circuit, this DTC is stored.

DTC Code

DTC Detection Condition

Trouble Area

C1241

When either of following conditions detected:

1. Both of following conditions continue for at least 10 seconds.

  • Vehicle speed more than 3 km/m (2 mph).
  • IG1 terminal voltage less than 9.5 V.

2. All of following conditions continue for at least 0.2 seconds.

  • Solenoid relay remains ON.
  • IG1 terminal voltage less than 9.5 V.
  • Relay contact open.
  • Battery
  • ECU-IG NO. 3 fuse
  • Charging system
  • Harness or connector
  • 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.

READ VALUE USING TECHSTREAM (IG VOLTAGE)

(a) Turn the ignition switch off.

(b) Connect the Techstream to the DLC3.

(c) Turn the ignition switch to ON.

(d) Turn the Techstream on.

(e) Start the engine.

(f) Enter the following menus: Chassis / ABS/VSC/TRAC / Data List.

ABS/VSC/TRAC

Tester Display

Measurement Item : Range

Normal Condition

Diagnostic Note

IG1 Voltage Value

IG1 voltage value/ Min.: 0.00 V, Max.: 20.00 V

11 to 14 V

Changes in proportion to battery voltage

(g) Measure the voltage output from the ECU displayed on the Techstream.

Result

Result

Proceed

Data display is within Normal Condition

A

Data display is not within Normal Condition

B
B

GO TO STEP 3

A

2.

RECONFIRM DTC

(a) Clear the DTCs (See page ). (b) Turn the ignition switch off. ).

(b) Turn the ignition switch off.

(c) Check if the same DTCs are output (See page HINT: HINT: ).

HINT:

Reinstall the sensors, connectors, etc. and restore the previous vehicle conditions before rechecking for DTCs.

Result

Result

Proceed to

DTC is output

A

DTC is not output (When troubleshooting in accordance with Diagnostic Trouble Code Chart)

B

DTC is not output (When troubleshooting in accordance with Problem Symptoms Table)

C
A

REPLACE MASTER CYLINDER SOLENOID

B

USE SIMULATION METHOD TO CHECK

C

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

3.

CHECK HARNESS AND CONNECTOR (IG1 TERMINAL)

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

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

S1-46 (IG1) - Body ground

Ignition switch ON

11 to 14 V
Text in Illustration

*a

Front view of wire harness connector

(to Skid Control ECU (Master Cylinder Solenoid))
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

4.

CHECK HARNESS AND CONNECTOR (GND TERMINAL)

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

S1-1 (GND1) - Body ground

Always

Below 1 Ω

S1-32 (GND2) - Body ground

Always

Below 1 Ω

S2-4 (GND3) - Body ground

Always

Below 1 Ω
Text in Illustration

*a

Front view of wire harness connector

(to Skid Control ECU (Master Cylinder Solenoid))
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

5.

RECONFIRM DTC

(a) Clear the DTCs (See page ). (b) Turn the ignition switch off. ).

(b) Turn the ignition switch off.

(c) Check if the same DTCs are output (See page HINT: HINT: ).

HINT:

Reinstall the sensors, connectors, etc. and restore the previous vehicle conditions before rechecking for DTCs.

Result

Result

Proceed to

DTC is output

A

DTC is not output (When troubleshooting in accordance with Diagnostic Trouble Code Chart)

B

DTC is not output (When troubleshooting in accordance with Problem Symptoms Table)

C
A

REPLACE MASTER CYLINDER SOLENOID

B

USE SIMULATION METHOD TO CHECK

C

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

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