Bendix Commercial Vehicle Systems EC-80 ABS ATC SD User Manual

Page 14

DIAGNOSTIC MODES

In order to communicate with the ECU, the controller has

several modes that the technician can select, allowing

information to be retrieved, or other ECU functions to be

accessed.

Diagnostic Modes

To enter the various diagnostic modes:

No. of

Times to

Press the

Blink Code

Switch

System Mode Entered

Active Diagnostic Trouble Code (DTC) retrieval

Inactive DTC retrieval

Clear active DTCs

System configuration check

Dynamometer Test Mode

Reconfigure ECU

* To enter the Reconfiguration Mode, the switch must be held

in before the application of ignition power. Once the power is

supplied, the switch is released and then pressed seven times.

CHART 3 - DIAGNOSTIC MODES

Active Diagnostic Trouble Code Mode

For troubleshooting, typically the active and inactive

Diagnostic Trouble Retrieval Modes are used. The

technician presses the blink code switch once and the ABS

indicator lamp flashes a first group of two codes, and if

there are more trouble codes recorded, this is followed by

a second set of codes, etc. (See page 18 for a directory of

these codes.) All active trouble codes may also be retrieved

using a hand‑held or PC‑based diagnostic tool, such as

the Bendix

ACom

Diagnostics software.

To clear active DTCs (as problems are fixed), simply clear

(or “self‑heal”) by removing and re‑applying ignition power.

The only exception is for wheel speed sensor trouble

codes, which clear when power is removed, re‑applied, and

the ECU detects valid wheel speed from all wheel speed

sensors. Alternately, codes may be cleared by pressing the

diagnostic blink code switch three (3) times (to enter the

Clear Active Diagnostic Trouble Code Mode) or by using

a hand‑held or PC‑based diagnostic tool. Hand‑held or

PC‑based diagnostic tools are able to clear wheel speed

sensor trouble codes without the vehicle being driven.

Inactive Diagnostic Trouble Code Mode

The ECU stores past trouble codes and comments (such

as configuration changes) in its memory. This record is

commonly referred to as “event history.” When an active

trouble code is cleared, the ECU stores it in the event

history memory as an inactive trouble code.

Blink Code Timing

The ECU responds with a sequence of blink codes. The

overall blink code response from the ECU is called a

“message.” Each message includes, depending on the

mode selected by the technician, a sequence of one or

more groups of blinks. Simply record the number of blinks

for each sequence and then use the troubleshooting index

on page 18 for active or inactive trouble codes. Once you

have located the code, you will be directed to the page

that provides the applicable troubleshooting information.
NOTE:
1. Blink sequences illuminate the ABS indicator lamp for

half a second, with half‑second pauses between them.

2. Pauses between blink code digits are 1.5 seconds.
3. Pauses between blink code messages are 2.5

seconds.

4. The lamp remains on for five (5) seconds at the end of

messages.

See Figure 8 for an example showing the message: 2,1

followed by 2,2.
Once the ABS indicator lamp begins displaying a sequence

of codes, it continues until all blink code messages have

been displayed and then returns to the normal operating

mode. During this time, the ECU will ignore any additional

blink code switch activation.
All trouble codes, with the exception of voltage and

J1939 trouble codes, will remain in an active state for the

remainder of the power cycle.
Voltage trouble codes will clear automatically when the

voltage returns within the required limits. All ABS functions

will be re‑engaged.
J1939 trouble codes will clear automatically when

communications are re‑established.