B2470

Symptom: ABS (ANTI LOCK) warning lamp on, no ABS function.

B2470

Fault symptom

ABS (ANTI LOCK) warning lamp on, no ABS function.

Condition

The trouble code is generated in the event of an open circuit lasting longer than 700 milliseconds. (In the event of a fault the system will be turned off immediately. If the system is in use it will not be turned off until activation ceases. A diagnostic trouble code will be stored when the system is turned off.)

Diagnostic help

A reading of the ON/OFF status of the brake light switch can be obtained with the ISAT scan tool.

-	Select "READ VALUES".

-	Select ”BRAKE LIGHT SWITCH”.

Diagnostic procedure

1 Check the brake light switch

-	Connect the ISAT scan tool. Ignition switch in the ON position.

-	Check the status of the brake light switch as described under "Diagnostic help" and depress and release the brake pedal.

Are the ISAT scan tool readings OK?

yes

Continue with point 3.

no

Continue with point 2.

2 Check the brake lights

-	Check that the brake lights work when the brake pedal is depressed.

Do the brake lights work?

yes

Check the wiring and connectors between pin 23 of the control module and the brake light switch. Rectify if necessary.

no

Continue fault diagnosis as described in Service Manual 3:2 Electrical system, brake lights .

3 Final check

-	Clear the diagnostic trouble code.

-	Drive the car at varying engine loads and rpm for 5 minutes.

-	Read the diagnostic trouble code.

Is the diagnostic trouble code stored?

yes

Continue with

no

The diagnostic procedure carried out was correct or the fault is of an intermittent nature.