Technical information

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Technician Guidelines for Antilock Braking Systems
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stop lamp and auxiliary circuit. Industry consensus is that
meeting this minimum recommendation will ensure adequate
power for trailer ABSs.
Additionally, TMC RP 141 recommends that:
• Pin 7 of the J560 connector be reassigned as a continu-
ous power circuit, activated when the ignition is on.
NOTE: For the purposes of RP 141, Pin 7 of the SAE
J560 seven-pin connector (so designated by SAE as the
auxiliary circuit) is referred to as the continuous power
circuit.
• There be a minimum of 9.5 volts (which includes a 1-
volt safety margin) available at the trailer ABS ECU—
when coupled to a tractor complying with RP 137— to
ensure adequate power for proper ABS operation.
• Trailer manufacturers provide equipment purchasers
with written information regarding the voltage and
current characteristics of the stop lamp and auxiliary
circuits at the SAE J560 seven-pin receptacle. TMC
recommends this information be included in the
owner’s manual.
TMC does not recommend specific wiring gauge sizes,
lighting technology, ABS power consumption, or grounding
methods. It is the consensus of TMC’s membership to leave
those decisions to the manufacturer/equipment user.
All vehicle/component manufacturers have agreed to
incorporate TMC’s recommendations into their vehicle design
as either standard or at the request of the equipment user.
9.5 Volts Minimum
at ABS ECU
12.5 Volts Minimum
at the seven-pin connector
(Pin 4 and 7)
Recommended Minimum Voltage for ABS
As Specified by TMC RPs 137 and 141