Toyota Tacoma manuals

Toyota Tacoma 2015-2018 Service Manual: Lost Communication with ECM (C1437)

DESCRIPTION

The skid control ECU (brake actuator assembly) receives signals from the ECM via the CAN communication system.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

C1437

Lost Communication with ECM

When voltage at terminal +BS is 10 to 17.4 V and vehicle speed is 15 km/h (9 mph) or more, data cannot be sent to ECM continuously for 2 seconds or more.

  • CAN communication system (skid control ECU to ECM)
  • Skid control ECU (brake actuator assembly)
  • ECM

CAUTION / NOTICE / HINT

NOTICE:

When replacing the skid control ECU (brake actuator assembly), perform zero point calibration and store system information (See page PROCEDURE PROCEDURE ).

PROCEDURE

1.

CHECK HARNESS AND CONNECTOR (MOMENTARY INTERRUPTION)

(a) Using the Techstream, check for any momentary interruption in the wire harness and connector corresponding to the DTC (See page ). ABS/VSC/TRAC ).

ABS/VSC/TRAC

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

EFI Communication Open

EFI communication open detection

Normal or Error

Normal

Error: Momentary interruption

EFI Communication Invalid

ECM communication invalid detection

Normal or Error

Normal

Error: Invalid

HINT:

Perform the above inspection before removing the sensor and connector.

OK:

Normal (There are no momentary interruptions.)

NG

CHECK CAN COMMUNICATION SYSTEM

OK

2.

RECONFIRM DTC

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

(b) Turn the ignition switch off.

(c) Start the engine.

(d) Drive the vehicle at a speed of 15 km/h (9 mph) or more for 10 seconds or more.

(e) Check that no CAN communication system DTC is output (See page (f) Check if the same DTC is recorded (See page (f) Check if the same DTC is recorded (See page ).

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

Result

Result

Proceed to

DTC C1437 is not output

A

DTC C1437 is output

B

CAN communication system DTC is output

C

A

USE SIMULATION METHOD TO CHECK

B

REPLACE BRAKE ACTUATOR ASSEMBLY

C

CHECK CAN COMMUNICATION SYSTEM

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Other materials:

Vehicle Speed Sensor Circuit (C1AA3)
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Inspection
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Removal
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