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Section 5 MERITOR WABCO

Diagnostics

WARNINGS

! To prevent serious eye injury, always wear safe eye protection when you perform

vehicle maintenance or service.

! The ABS is an electrical system. When you work on the ABS, take the same precautions

that you must take with any electrical system to avoid serious personal injury.

As with any electrical system, the danger of electrical shock or sparks exists that can

ignite flammable substances. You must always disconnect the battery

ground cable before working on the electrical system.

Introduction

Blink code diagnostic procedures in this section cover:

ECU Part Number 472 500 011 0

Meritor WABCO Basic ECU without an external diagnostic connector

ECU Part Number:

472 500 001 0

472 500 012 0

472 500 013 0

Meritor WABCO ECUs with external diagnostic connectors

This section covers Normal Mode diagnostics (Codes for system faults

that cause the ABS warning lamp to come on and stay on when the vehicle is in operation.)

NOTE

For ECU Part Numbers 472 500 012 0 and 472 500 013 0 ONLY:

If you do not have a diagnostic blink code tool, follow the procedure given for ECU 472 500 011 0

(see "Using the Blink Code" in this section), but use Table E - Normal Mode Fault Code

Table to identify the fault codes.

For additional diagnostic procedures refer to:

Appendix A Expert Mode Diagnostics

(ECU P/Ns 472 500 001 0,

472 500 012 0, 472 500 013 0)

This mode is used to identify

intermittent faults, such as a

loose connector:

Appendix B Reconfigure Mode. Use only as

indicated in the reconfiguration

table in Appendix B.

Appendix C Warning Lamp Diagnostics

(ECU P/Ns 472 500 011 0,

472 500 012 0, 472 500 013 0)

Blink Code Diagnostics

To use blink code diagnostics you need to know whether or not the ECU

has an external diagnostic connector. See Section 2, "System Components"

in this manual for details. If you are unable to make this determination,

contact the Meritor Customer Support Center at 800-535-5560 for assistance.

On-Site Assistance

Meritor WABCO has provided an ABS Trailer warning label that illustrates

possible system fault locations. This label should be mounted on the trailer

near the ABS warning lamp. If there is no ABS warning label on the trailer,

let your supervisor know. Labels are available from Meritor WABCO.

Ask for Part Number TP-95172.

Page 21

TABLE OF CONTENTS

Using the Blink Code

For ECU Part Number 472 500 011 0 without diagnostic connector:

Make sure the vehicle is stationary:

· Emergency brake ON

· Wheels properly chocked

Provide 12 volts DC power (9.5 to 14 volts is acceptable range) to the ECU/Valve Assembly.

Check the ABS warning lamp on the trailer. If:

· The warning lamp comes ON briefly, then goes OFF: There is no fault in system.

· The warning lamp comes ON and stays ON:

There is an existing fault. Go to Step 4.

Check the blink code lamp on the ECU. See Figure 5.1.

· If blink code lamp is OFF, there is no system fault.

· If the blink code lamp is flashing, count the number of flashes

to identify the fault. Check Table D – ECU Part Number

472 500 011 0 Blink Codes to determine the problem.

Follow the suggested corrective action.

Figure 5.1

Table D – ECU Part Number 472 500 011 0 Blink Codes

Blink Code Problem Area Action

4 Sensor YE1 (curbside sensor)
Check sensor installation and connections.

Verify proper sensor resistance and air gap.

Make necessary repairs.

6 Sensor YE2 (roadside sensor)
Check sensor installation and connections.

Verify proper sensor resistance and air gap.

Make necessary repairs.

10 ECU/Valve Assembly
Verify proper installation. Make sure all connections are secure.

If code continues, contact Meritor WABCO for assistance.

14 Power Supply
Verify proper electrical installation and connections.

Check power supply.

Make necessary corrections.

15 ECU Failure
Verify proper installation.

If code continues, contact Meritor WABCO for assistance

TABLE OF CONTENTS

Diagnostic Tools For ECUs with External Diagnostic Connectors

MPSI Pro-Link® 9000 Diagnostic Tool

(Meritor WABCO Cartridge Model J 38500-404)

The MPSI Pro-Link® 9000 diagnostic tool can test for existing and stored faults, read and clear fault codes, and test components, for Meritor WABCO tractor and trailer ABS.

Figure 5.2

Kent-Moore offers Kit J 38500-404 that contains the Meritor WABCO ABS diagnostic cartridge, version 4.0 or higher, and the manual "Meritor WABCO ABS/ATC Systems," which contains complete information and operating instructions for the MPSI Pro-Link® 9000 diagnostic tool. Order the kit from Kent-Moore, 28635 Mound Road, Warren, Ml 48092-3499; phone 800-345-2233.

NOTE

A J 38500-60A Deutsch cable is also required. It is available from Kent-Moore.

Diagnostic Activation Tool

For ECU Part Numbers 472 500 001 0, 472 500 012 0 and 472500 013 0.

Figure 5.3

The blink code diagnostic tool inserts into the SAE J1587 diagnostic connector to activate the blink code diagnostics, reconfigure the ECU and test ECU installation. (See "How to Install the Blink Code Diagnostic Tool into the SAE J1587 Diagnostic Connector" in Section 6, "Component Replacement".)

Normal Mode Diagnostics

NOTE

If the blink code lamp displays a blink code for a fault that is not listed in the Normal Mode Fault Code Table or the Expert Mode Fault Code Table in Appendix A:

1. Visually inspect all connections and components.

Try to erase the fault from ECU memory. If you cannot erase the fault, a problem can exist within the ECU/VaIve Assembly.

Contact the Meritor Customer Support Center at 800-535-5560.

TABLE OF CONTENTS

How to Test for Existing Faults Using the Normal Mode

When you use Normal Mode diagnostics, the blink code lamp displays a numerical fault code sequence for each existing fault, one at a time. If the ECU stores more than one existing fault in memory, you must repair the first fault before Normal Mode diagnostics will display the second existing fault. In the Normal Mode, the lamp only identifies the component that needs repair; for example, THREE FLASHES = SENSOR BU1. To identify and display intermittent faults, use Expert Mode diagnostics. (See Appendix A.)

The ECU stores existing faults into memory in the order in which they occur, but the blink code lamp displays the most recent fault first. To identify and display intermittent stored faults (such as a loose cable or wire) from ECU memory, you must use Expert Mode diagnostics.

To activate Normal Mode diagnostics:

1. The vehicle must be stationary. Power the ECU with 12 volts DC (9.5-14 is an acceptable range). The warning lamp on the trailer will come ON.

2. Locate the diagnostic tool: Plug the diagnostic tool into the diagnostic cable socket located usually on the right side of the trailer sub-frame.

Figure 5.4

3. Press the blink code switch once for one second and release the switch.

4. If there are no existing faults in the system: When activated, the blink code lamp will

- Come ON

- Go OFF

- Remain OFF

5. When there is an existing fault: The blink code lamp will flash between three and fifteen times to identify the existing fault. Refer to Table E -Normal Mode Fault Code Table, below, for Normal Mode fault codes. See Figure 5.5.

6. When there are existing faults: You must repair existing faults.

7. After you identify an existing fault, turn the power to the ECU OFF. Repair the fault. Turn the power to the ECU back ON.

8. ECU Part Number 472 500 001 0: Repeat Steps 3, 5, 6, and 7 until the blink code lamp goes OFF, comes back ON and remains ON. This sequence signals that there are no other existing faults.

ECU Part Numbers 472 500 012 0 and 472 500 013 0: Repeat Step 3. If there are no other existing faults in the system, the blink code lamp will come ON, go OFF and remain OFF.

9. If you have just repaired a sensor fault, the ECU is "waiting" to see a 4-mph signal on sensed wheels. Until this 4 mph is sensed by the ECU, the ABS warning lamp on the trailer will remain ON.

TABLE OF CONTENTS

Table E - Normal Mode Fault Code Table

Blink Code	Location
0	No Faults
3	Sensor BU1
4	Sensor YE1
5	Sensor BU2
6	Sensor YE2
7	Ext. Modulator (Red) 4S/3M Only
9	Ext. Modulator (BU)
10	ECU Modulator (YE)
14	System Configuration/Power Supply
15	ECU Failure

Figure 5.5

TABLE OF CONTENTS

Repair Existing Faults

· With Normal Mode diagnostics, you must repair an existing fault before you can identify and repair the next existing fault stored in ECU memory. Follow these steps:

Turn off the power to the ECU.

· Repair the fault.

· Repeat Normal Mode diagnostics. Clear stored faults (if necessary).

Clear stored faults (if necessary).

How to Clear Repaired Faults from the ECU

1. Power the ECU with 12 volts DC (9.5-14.0 is an acceptable range).

2. To clear repaired faults from ECU memory, press the blink code lamp switch three times for one second each time as follows:

a. Depress the blink code lamp switch once for one second. The lamp will come ON.

b. Release the switch for one second. The lamp will go OFF.

c. Immediately depress the switch once for one second. The blink code lamp will come back ON.

d. Immediately release the switch once for one second. The blink code lamp will go OFF.

e. Immediately depress the switch once for one second. The blink code lamp will come back ON.

f. Release the switch.

g.The blink code lamp will flash rapidly for eight times to indicate that the repaired faults have been erased from ECU memory.

The lamp will continue to flash the system configuration until you turn OFF the power to the ECU. System configuration codes are:

- 2 Flashes = 4S/3M

- 3 Flashes = 4S/2M

- 4 Flashes = 2S/2M

- 5 Flashes = 2S/1M

Blink Code Example (4S/2M Configuration)

Clear-All Mode

Figure 5.6

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