WABCO iABS 2S/1M Standard, Maintenance Manual

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ABS Questions and Answers
What if a tractor has one manufacturer’s ABS with PLC and the trailer has another manufacturer’s
ABS with PLC? Will the two systems be compatible and operate the trailer ABS lamp as expected?
Yes. ABS with PLC from different manufacturers are designed to be compatible by controlling the trailer
ABS lamp according to the FMVSS-121 standard, even when systems from different manufacturers are
connected to each other. However, certain features beyond the control of the trailer ABS indicator lamp may
or may not be supported by all devices communicating via PLC. SAE task forces continue to standardize
common messages so that maximum compatibility may exist in the future.
How do I diagnose PLC?
PLC can be diagnosed anywhere you can connect to the main power wire on the trailer, typically tools are
designed to be plugged into the J560 connection at the nose of the trailer.
Can I use blink code diagnostics on iABS to diagnose PLC?
Yes. Section 5 of this manual describes the method of performing a blink code check using Constant Power
(ignition activation). Blink Code 17 indicates a PLC failure.
If PLC does not seem to be operating correctly, but I don’t get a Blink Code 17 when I run a blink
code check, what else could be wrong?
If there is no Blink Code 17, the ECU is functioning correctly and does not need to be replaced; however,
there could be a problem in the trailer’s wiring harness. Check the wiring system and make the necessary
repairs. If the problem persists, contact the WABCO Customer Care Center at 855-228-3203.
4.3 ABS Indicator Lamps
When replacing the bulb, to ensure correct lamp operation use an incandescent type DOT-
approved lamp, or a LED with integral load resistor.
4.3.1 ABS Indicator Lamp (on Dash)
With iABS, there are two ABS indicator lamps; one on the vehicle dash and one on the side of the trailer.
Refer to Appendix I for information about the operation of this lamp.
4.3.2 ABS Indicator Lamp (on Trailer)
What is the function of the ABS indicator lamp?
The indicator lamp enables a driver to monitor the ABS at all times. Refer to the DOT requirements for the
mounting location of the indicator lamp.
How does the indicator lamp operate?
How the indicator lamp operates depends on whether the ABS is powered by stoplight or constant power:
 If the trailer was manufactured prior to February 28, 1998, or was manufactured outside of the United
States, the ABS may be either stoplight or constant powered.
 If the trailer was manufactured March 1, 1998 or later — and was manufactured in the United States
— it will have constant power capability. This is mandated by Federal Motor Vehicle Safety Standard
(FMVSS) 121.
Check your trailer speci fi cation sheet to determine the type of ABS power. Table B in this section illustrate
indicator lamp operation on stoplight and constant powered ABS systems.