1. Hydraulic Anti-Lock Braking System For Trucks, Buses and Motor Homes

2. The World Leader in ABS for Heavy-Duty Commercial Vehicles Offers State-of-the-Art Systems The World Leader in ABS for Heavy-Duty Commercial Vehicles Offers State-of-the-Art Systems In Production Since 1989 with Range Rover Development Started in 1985 Over 1,000,000 Systems Produced Hydraulic ABS

3. Required on vehicles produced after March 1, 1999 All vehicles over 10,000 lbs GVW Minimum 4S / 3M system Federal Mandate

4. Hydraulic ABS Enhance stability Maintain steerability Improve stopping distances Stabilize insurance costs Reduction in number and severity of accidents Reasons For ABS

5. Features of Hydraulic ABS Hydraulic ABS Robust design inspired by heavy-duty pneumatic ABS (sensors, sealing, etc.) Optimized performance of retarders Optimized performance of wide range of tire sizes (more than one ECU) Both cab and frame mounted ECU’s

6. Modulator Assembly Connector Pin Assignment MAIN GROUND FOR MODULATOR ASSEMBLY Pin Number Circuit Description Pin Number Circuit Description 12345671234567 Outlet Valve RL Inlet Valve RL - - - - - - - Inlet Valve FR Outlet Valve FR - - - - - - - 8 9 10 11 12 13 Reference Ground - - - - - - - Outlet Valve RR Inlet Valve RR Inlet Valve FL Outlet Valve FL

7. Identifying D-Version Hydraulic ABS Codes Loose or burned out bulb Voltage not within acceptable range (9.5 to 14 volts DC) Repair or replace lamp bulb Measure voltage, check connections, make necessary repairs ABS indicator lamp does not come on Check ABS indicator lamp for blink codeABS indicator lamp comes on briefly then goes out No further action requiredIf ONE blink code is displayed System OK Go to Step 2If ONE blink code other than 1-1 is continuously displayed System fault exists Go to Step 3If a series of codes are displayed Stored faults in system Step 1 Turn ignition key ON. DO NOT turn engine on. Press Blink Code Switch once, then release Step 2 Repair fault Find blink code on TABLE C* Turn off the ignition Repair the fault Clear the fault (go to Step 3) No further action requiredABS indicator lamp displays blink code 1- 1, then goes OFF System OK Step 3 Clear fault Turn ignition key ON. DO NOT turn engine on. Press Blink Code Switch. HOLD FOR 3 SECONDS. RELEASE Drive the vehicle at a speed of 4 mph (6 km/h). Once the ECU senses wheel speed, the lamp will go OFF If the ABS indicator lamp displays blink code 1-1, goes OFF, then comes back on and stays ON System looking for wheel speed. This occurs after a sensor fault ResponseStatusAction If you receive a blink code that is not identified in TABLE C, contact the Meritor Customer Support Center at 800-535-5560 *

8. Ignition Key ON to determine ABS blink code fault IV Ignition Key OFF to test system (except where noted) 12345 Correct Volt Ohm Meter Readings Fault Code Problem AreaConnector Pins to be Tested Action 1-1System OKNone required 2-1RIGHT FRONT Solenoid valve (inlet or outlet valve) failure in modulator, wiring harness or inside ECU 2-1RIGHT FRONT Solenoid valve (inlet or outlet valve) failure in modulator, wiring harness or inside ECU 2-1RIGHT FRONT Solenoid valve (inlet or outlet valve) failure in modulator, wiring harness or inside ECU 2-1RIGHT FRONT Solenoid valve (inlet or outlet valve) failure in modulator, wiring harness or inside ECU 2-1RIGHT FRONT Solenoid valve (inlet or outlet valve) failure in modulator, wiring harness or inside ECU 15-pin IV 3 to chassis ground 5 and 3 2 and 3 1 and 3 8 and 3 OV 4 and 3 1 and 3 10 and 3 7 and 3 0 volt Inlet valve: 6.5 + 0.5 ohms Outlet valve: 3.5 + 0.5 ohms Check electrical resistance of affected valve wiring to ground at ECU vehicle connector and at modulator plug Check voltages at wiring harness and connectors. Voltage of ground connector should be approximately 0 volts. Make necessary repairs Check ABS ground connections. Make necessary repairs OV= Inlet Valve= Outlet Valve D Version Hydraulic ABS Blink Codes

9. Ignition Key ON to determine ABS blink code fault Ignition Key OFF to test system (except where noted) 12345 Correct Volt Ohm Meter Readings Fault Code Problem AreaConnector Pins to be Tested Action 3-1RIGHT FRONT sensor - Air gap 9-pin Check for sensor adjustment. Check for excessive wheel bearing endplay. Repair or replace as needed 3-2LEFT FRONT sensor - Air gap 3-3RIGHT REAR sensor - Air gap 3-4LEFT REAR sensor - Air gap 9-pin Greater than.2 volts AC at 30 RPM (Rotate wheel 1/2 revolution per second) 4 and 5 1 and 2 3 and 6 7 and 8 4-1 RIGHT FRONT sensor - Electrical Fault 9-pin4 and 5 4-2LEFT FRONT sensor - Electrical Fault 9-pin1 and 2 4.3RIGHT REAR sensor - Electrical Fault 9-pin3 and 6 4.4LEFT REAR sensor - Electrical Fault 9-pin7 and 8 5.1RIGHT FRONT wheel - Erratic wheel speed 5.2LEFT FRONT wheel - Erratic wheel speed 5.3RIGHT REAR wheel - Erratic wheel speed 5.4LEFT REAR wheel - Erratic wheel speed 500-2000 ohms Check electrical resistance of affected sensor and wiring at ECU connector and at harness plugs. Repair or replace as needed Check for tire size mismatch or tooth wheel difference. Check sensor cable and connector for intermittent contact. Repair or Replace as needed Verify proper connections to relay. (See wiring diagram) Check bulb. Repair or replace as needed.70 7.3Retarder Relay 7.4ABS warning lamp D Version Hydraulic ABS Blink Codes (Con’t.)

10. Ignition Key ON to determine ABS blink code fault Ignition Key OFF to test system (except where noted) 12345 Correct Volt Ohm Meter Readings Fault Code Problem AreaConnector Pins to be Tested Action 7-7Recirculation pump does not switch off 18-pin8 and 12 0 volt Check the recirculation pump wiring, the pump relay and fuse and pump connections. Repair or replace as needed Recirculation pump does not switch on (low level with act) OR TURN IGNITION ON 12 volts DC 7-8Recirculation pump does not switch off 18-pinLink pins 2 and 8 TURN IGNITION ON Excessive current failure. If pump does not run when pins are linked, replace modulator assembly 8-1No voltage to ABS solenoid valves 18-pin1 and 212 volts DC TURN IGNITION ON Check the valve relay, fuse and wiring. Repair or replace as needed 8-2Continuous supply to ECU with ignition off 18-pin5 and 120 voltsCheck for proper wiring connections. Make necessary repairs 8-3Internal ECU faultReplace ECU D Version Hydraulic ABS Blink Codes (Con’t.)

11. Benefits To The User Stops shorter on most surfaces Stability Ability to steer

12. Steering Wheels Locked PLOW OUT (Can’t Steer) Rear Wheels Locked FISH TAIL (Back End Swings Out)

13. Hydraulic ABS Electrical System - 4 Channel System Layout 4 Channel ECU + 12 Volts Ground ABS Valve Assembly

14. Hydraulic ABS Hydraulic System Layout Hydraulic Brake Lines Hydraulic ABS Valve Assembly to ECU Cable Power Plug for Valve Assembly Motor Hydraulic Brake Lines

15. Hydraulic Anti-lock Brake System 76 Closed Loop Control System Sensor Tooth Wheel ECU Hydraulic ABS Valve Assembly

17. Pump Motor Rear Axle Front Axle Hydraulic ABS Valve Assembly Hydraulic Layout Check Valve (4) Solenoid (4) NO NC Accumulator NO = Normally Open NC = Normally Closed Solenoid (4)

18. Valve Assembly Pressure Increase Hydraulic Layout Hydraulic ABS Pump Motor Rear Axle Front Axle

19. Hydraulic ABS Pump Motor Rear Axle Front Axle Valve Assembly Pressure Decrease Hydraulic Layout

20. Hydraulic ABS Pump Motor Rear Axle Front Axle Valve Assembly Pressure Hold Hydraulic Layout

21. Hydraulic ABS Cab Mount ECU Wiring Diagram

22. Hydraulic ABS Frame Mount ECU Wiring Diagram

23. Hydraulic ABS Blink code diagnostics PC diagnostics Maintenance manual no. 39 Meritor customer service center 1-800-535-5560 On-site training Diagnostics