Diagnostic Instructions
Diagnostic Aids
Important: Upon replacing the electronic brake control module (EBCM) perform the Bendix RDU magnet reset procedure. Refer to
Status Lamp Resetting.
An inoperative light emitting diode (LED) on the Bendix Remote Diagnostic Unit (RDU) may cause the RDU to illuminate an invalid combination of LEDs. This does not however, indicate that the EBCM is non-functional or needs to be replaced. You may be able
to navigate to the correct diagnostic procedure by determining which LED is inoperative and combining the displayed LEDs with an inoperative LED in order to create a valid diagnostic fault display. For example:
| • | The Bendix RDU illuminated LFT, STEERAXLE LEDs. |
| • | A technician finds that the RDU is indicating a LFT, STEERAXLE modulator diagnostic fault. |
If using the specified procedure does not indicate a valid fault, or if more than one LED is found to be inoperative, the Bendix RDU may need to be replaced.
The following may also be some possible sources for communication problems of the RDU:
| • | The ECU does not support PID 194. |
| • | No power is being supplied to the ECU and/or the RDU. |
| • | A malfunctioning RDU unit |
Reference Information
Schematic Reference
Air Antilock Brake System Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Air ABS Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References
Circuit/System Verification
Ignition ON, verify the status lamp resetting procedure
Status Lamp Resetting. If the ABS ECU does not respond to the Bendix RDU tool request for DTCs the Red LEDS on the RDU tool should all illuminate individually
in a clockwise manner.
| ⇒ | If the communication state of the RDU is down. Refer to the Diagnostic Aids. |
| ⇒ | If the status lamps resetting procedure works, replace the EBCM. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for EBCM replacement, setup, and programming
For Bendix tool RDU replacement, refer to your local Bendix account manager or 1-800-AIR-BRAKE.
Repair Verification
Ignition ON, observe the Bendix RDU tool after the ignition has been ON for 10 seconds. Does the Bedix RDU only illuminate a green VLT LED.
| ⇒ | If the specified value is displayed, system is OK. |
