Self Diagnosis Function

T-Series 2.0:When the brake pedal switch is operated, battery voltage is switched from fuse 41 in the engine compartment fuse box on the W/Y wire to the modulator on the G/W wire.

L-Series:When the brake pedal switch is operated, battery voltage is switched from fuse 2 in the passenger compartment fuse box on the B/Y wire to the modulator on the G/P (LHD) or G/W (RHD) wire.

Electrical connections between the modulator and the left rear, the right rear, the right front and the left front wheel sensors, are made on the P-S, G/Y-U/Y, G/B-G and G/U-N wires, respectively.

Self Diagnosis Function

The ECU has a self diagnosis function. If a fault is detected, the ABS system will not operate and the ABS warning light will illuminate, staying ON until the ignition switch is turned OFF. If the fault is still present when the ignition is next switched ON, the warning light is lit; but if the fault is absent, the warning light is not lit and a fault code is stored in the ECU memory. If the fault is not detected for 20 operations of the ignition switch, the fault code is deleted from ECU memory. Access to the ECU memory for fault code retrieval, can be gained via TestBook.

NOTE: The fault could either be in the specific component or in the associated wiring.

Failure of Components

Before replacing major components like the ECU or the modulator, ensure that a thorough diagnosis of the fault has been carried out. Failure of these components is rare. Usually, such a fault lies within the associated wiring or connections to the component and not in the component itself.

Ensure that the fault code memory is clear so that if any further problems occur, the fault codes stored in the memory relate to the current problem and not to a previously repaired fault.