939003592 - F002 REAR WHEELS LOCK WHILST BRAKING

When the brakes are operated the distribution between the front and rear wheels is not correct: in extreme conditions the rear wheels lock and the vehicle may skid
0PRELIMINARY CHECKSALL OKPROBLEMS ENCOUNTEREDACTION
First of all check whether the ABS warning light and the handbrake warning light come on simultaneously during starting and then go outMove on to Step 1The two warning lights remain on after startingProceed as instructed in the    See table K062 ABS AND HANDBRAKE WARNING LIGHTS BOTH ON
1CHECK USING DIAGNOSTIC EQUIPMENTALL OKPROBLEMS ENCOUNTEREDACTION
Connect the diagnostic test equipment (Examiner or other instruments) to the tester input.Check that there are no faults in the ABS control unit.Move on to Step 21. Error detected in the control unit.1. Continue following the instructions for the diagnostic equipment
2. No communication with the control unit.2. Restore:

  • Connection between the ABS control unit and the diagnostic connector;
  • ABS control unit supply
    See E7020 ABS
2ACTIVE DIAGNOSIS WITH DIAGNOSTIC EQUIPMENTALL OKPROBLEMS ENCOUNTEREDACTION
Connect the diagnostic equipment (Examiner or other instruments) and carry out the active diagnosis for:

  • Pump motor;
  • Solenoid valves.
Move on to Step 3Fault detected in one of the solenoid valves.Replace the ABS electronic control unit electrohydraulic unit    Op. 3340A12 ABS HYDRAULIC AND ELECTRONIC CONTROL UNIT - R.R.
3REAR BRAKE CALIPER CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Check the condition of the rear brake caliper pistons.Move on to Step 4Pistons worn or seized.Replace the rear brake calipersOp. 3310B34
4CHECK ON FLEXIBLE BRAKE PIPES AND BLEEDINGALL OKPROBLEMS ENCOUNTEREDACTION
Visually inspect that there are no bends or constrictions in the brake pipes, bleed the system and check that the fluid comes out evenly from the bleed screws.    Op. 0010T65 HYDRAULIC BRAKE SYSTEM - BLEED AIR Move on to Step 5Bends or constrictions present, the fluid does not come out evenly.Replace the section of pipe affected by the problem    Op. 3340B ABS SYSTEM PIPES
5FRONT BRAKE STATE CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Visually inspect that there is no grease, oil or dirt on the braking surfaces of the front pads.End of diagnosisBraking surfaces dirty.Clean, check and eliminate the causes of the problem: if necessary, replace the front pads    Op. 3310A60 FRONT BRAKE PADS - REPLACE