Last Modified: 7-3-2017 6.8:8.0.40 Doc ID: RM000001A5J007X
Model Year Start: 2007 Model: LX470 Prod Date Range: [08/2006 -           ]
Title: BRAKE CONTROL: VEHICLE STABILITY CONTROL SYSTEM: C1203/53,C1203/59; ECM Communication Circuit Malfunction; 2007 MY LX470 [08/2006 -        ]

DTC

C1203/53

ECM Communication Circuit Malfunction

DTC

C1203/59

ECM Communication Circuit Malfunction

DESCRIPTION

The circuit is used to send TRAC & VSC control information from the skid control ECU (TRC+, TRC-) to the translate ECU, and engine control information from the translate ECU to the skid control ECU (ENG+, ENG-).

DTC No.

DTC Detection Condition

Trouble Area

C1203/53

Both of following conditions are met:

  1. IG1 voltage is 9.5 V or more, and condition that signals cannot be transmitted to translate ECU occurs continuously for 5 seconds or more
  2. IG1 voltage is 9.5 V or more, and condition that signals cannot be received from translate ECU occurs continuously for 5 seconds or more
  • TRC+- communication line
  • ENG+- communication line
  • Skid control ECU assembly
  • Translate ECU

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1.

CHECK WIRE HARNESS (SKID CONTROL ECU ASSEMBLY - TRANSLATE ECU)

(a) Disconnect the A40 and T39 ECU connectors.

(b) Measure the resistance of the wire harness side connectors.

Standard resistance:

Tester Connection

Specified Condition

A40-14 (ENG+) - T39-14 (ENG+)

Below 1 Ω

A40-16 (TRC-) - T39-17 (TRC-)

Below 1 Ω

A40-22 (ENG-) - T39-15 (ENG-)

Below 1 Ω

A40-24 (TRC+) - T39-16 (TRC+)

Below 1 Ω
NG

REPAIR OR REPLACE HARNESS AND CONNECTOR

OK

2.

CHECK ECU COMMUNICATION (SKID CONTROL ECU - TRANSLATE ECU)

(a) Remove the skid control ECU.

(b) Connect an oscilloscope to terminals ENG+ and ENG- or TRC+ and TRC- of skid control ECU.

(c) Start the engine, and check the signal waveform.

OK:

A waveform is output, as shown in the illustration.

NG

REPLACE SKID CONTROL ECU

OK

REPLACE TRANSLATE ECU