Pinpoint Test I: Poor Vehicle Tracking During Anti-Lock Function

Test Step 

1. I1 CHECK THE BASE BRAKE SYSTEM 
   • Inspect the base brake system.
   • Is the base brake system OK? 

   Result / Action to Take 

   1. Yes:  GO to I2.
   2. No:  REFER to DISC .
2. I2 BLEED THE BRAKE SYSTEM 
   • Bleed the brake system. Refer to BLEEDING BRAKE SYSTEM .
   • Does the vehicle track poorly? 
   1. Yes:  GO to I3.
   2. No:  The brake system is operating correctly. REPEAT the self-test.
3. I3 CHECK THE LF ABS VALVE OPERATION 
   • Lift the vehicle and rotate all the wheels to make sure they rotate freely (the vehicle must be in neutral).
   NOTE: The trigger must be pressed twice.
   • Each press runs the pump motor for two seconds.
   • Trigger ABS module active command PMP MOTOR ON for four seconds.
   • Apply moderate brake pedal effort.
   • Have an assistant attempt to rotate the LF wheel while the pump motor is running.
   • Does the LF wheel rotate? 
   1. Yes:  INSTALL a HCU. REFER to HYDRAULIC CONTROL UNIT . REPEAT the self-test.
   2. No:  GO to I4.
4. I4 CHECK THE LF ABS VALVE RELEASE 
   • Apply moderate brake pedal effort.
   NOTE: The trigger must be pressed twice.
   • Each press runs the pump motor for two seconds.
   • Trigger the ABS module active command LF INLET and LF OUTLET.
   • Have an assistant attempt to rotate the LF wheel immediately after pressing the trigger.
   • Does the LF wheel rotate? 
   1. Yes:  GO to I5.
   2. No:  GO to  I11.
5. I5 CHECK THE RF ABS VALVE OPERATION 
   NOTE: The trigger must be pressed twice.
   • Each press runs the pump motor for two seconds.
   • Trigger the ABS module active command PMP MOTOR ON for four seconds.
   • Apply moderate brake pedal effort.
   • Have an assistant attempt to rotate the RF wheel while the pump motor is running.
   • Does the RF wheel rotate? 
   1. Yes:  INSTALL a HCU. REFER to HYDRAULIC CONTROL UNIT . REPEAT the self-test.
   2. No:  GO to I6.
6. I6 CHECK THE RF ABS VALVE RELEASE 
   • Apply moderate brake pedal effort.
   NOTE: The diagnostic tool will energize the valves for only two seconds per trigger press.
   • Trigger the ABS module active command RF INLET and RF OUTLET.
   • Have an assistant attempt to rotate the RF wheel immediately after pressing the trigger.
   • Does the RF wheel rotate? 
   1. Yes:  GO to I7.
   2. No:  GO to  I8.
7. I7 CHECK THE LR ABS VALVE OPERATION 
   NOTE: The trigger must be pressed twice. Each press runs the pump motor for two seconds.
   • Trigger the ABS module active command PMP MOTOR ON for four seconds.
   • Apply moderate brake pedal effort.
   • Have an assistant attempt to rotate the LR wheel while the pump motor is running.
   • Does the LR wheel rotate? 
   1. Yes:  INSTALL a new HCU. REFER to HYDRAULIC CONTROL UNIT . REPEAT the selftest.
   2. No:  GO to I8.
8. I8 CHECK THE LR ABS VALVE RELEASE 
   • Apply moderate brake pedal effort.
   NOTE: The diagnostic tool will energize the valves for only two seconds per trigger press.
   • Trigger the ABS module active command LR INLET and LR OUTLET.
   • Have an assistant attempt to rotate the LR wheel immediately after pressing the trigger.
   • Does the LR wheel rotate? 
   1. Yes:  GO to I9.
   2. No:  GO to  I11.
9. I9 CHECK THE RR ABS VALVE OPERATION 
   NOTE: The trigger must be pressed twice.
   • Each press runs the pump motor for two seconds.
   • Trigger the ABS module active command PMP MOTOR ON for four seconds.
   • Apply moderate brake pedal effort.
   • Have an assistant attempt to rotate the RR wheel while the pump motor is running.
   • Does the RR wheel rotate? 
   1. Yes:  INSTALL a new HCU. REFER to HYDRAULIC CONTROL UNIT . REPEAT the selftest.
   2. No:  GO to I10.
10. I10 CHECK THE RR ABS VALVE RELEASE 
    • Apply moderate brake pedal effort.
    NOTE: The diagnostic tool will energize the valves for only two seconds per trigger press.
    • Trigger the ABS module active command RR INLET and RR OUTLET.
    • Have an assistant attempt to rotate the RR wheel immediately after pressing the trigger.
    • Does the RR wheel rotate? 
    1. Yes:  The ABS is operating correctly.
    2. No:  GO to I11.
11. I11 CHECK FOR DTCs 
    • Carry out the ABS module self-test.
    • Are any DTCs retrieved? 
    1. Yes:  GO to the ANTI-LOCK BRAKE SYSTEM (ABS) MODULE DIAGNOSTIC TROUBLE CODE (DTC) INDEX .
    2. No:  INSTALL a new HCU. REFER to HYDRAULIC CONTROL UNIT . TEST the system for normal operation.