ABS warning lamp: Notes

Fig 1: Identifying ABS Warning Lamp

Courtesy of SAAB-SCANIA OF AMERICA, INC.

The ABS, TC/ABS or ESP control modules monitor the function of the ABS system and on a fault turn on the ABS warning lamp which is located in the RH part of the main instrument.

When the ABS lamp lights up, the anti-lock braking system is disabled and the brakes work just like a conventional braking system.

In cars with ABS (not bus-connected system)  the ABS control unit grounds pin 7 in the main instrument whereupon the control module lights the warning lamp.

Fig 2: Identifying ABS (Not Bus-Connected System) Communication Flow Line

Courtesy of SAAB-SCANIA OF AMERICA, INC.

Fig 3: ABS (Not Bus-Connected System) - Circuit Diagram

Courtesy of SAAB-SCANIA OF AMERICA, INC.

In cars with TC/ABS or ESP (bus-connected system)  , the main instrument receives information on the bus to turn the lamp on/off.

The TC/ABS or ESP control module lights the lamp when the ignition is turned on, if there is no fault the lamp goes off after around 3 seconds.

When the ABS warning lamp is lit, the central warning lamp comes on and at engine speeds higher than 300 RPM, MIU sends a request to SID to activate the acoustic signal.