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Home >> Lexus >> 1992 >> LS 400 >> Repair and Diagnosis >> Brakes >> Traction Control >> Traction Control System >> Diagnostic Charts >> Code 11 & 12: TRAC Brake Main Relay Circuit >> Circuit Description
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Circuit Description

This relay circuit supplies power to each traction brake actuator solenoid. When the ignition switch is turned on, the relay goes on. If trouble occurs in this relay circuit, the ECU cuts off current to the TRAC brake main relay and prohibits the traction control (Fail safe function).

CODE 11 & 12 DIAGNOSTIC

Code No. Diagnosis Trouble Area
11 When the ECU is sending an ON signal to the TRAC brake main relay, terminals SRC, SMC, SAC of the ECU are all 0V. TRAC brake main relay. (Remains OFF) Harness or connector between TRAC brake main relay and ECU. (Open or short in TSR, R- harness) Harness or connector between TRAC brake main relay and TRAC brake actuator. (Open) ECU
12 When the ECU is not sending an ON signal to the TRAC brake main relay, any of terminals SRC, SMC, SAC is battery voltage. TRAC brake main relay. (Remains ON) Harness or connector between TRAC brake main relay and TRAC brake actuator. (+B short) ECU
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