Inspection Bulletin 2013-02 Antilock Brake Systems - ABS Malfunction Lamp

Cited for an ABS malfunction light (dash-mounted trailer light) being illuminated - ABS dash mounted light for the trailer was illuminated when it was inspected with the air system below 50 psi. The abs system on this trailer is Meritor WABCO. Please reference the enclosed documents regarding the response from Meritor WABCO, photo of ABS ECU and inspection report. In summary, the system was working properly however the ECU sent a fault because the air pressure was below 50 psi. which was directly the result of the inspection process(brake light checks, low air warning, tractor protection etc..). If the unit was at normal operating air pressure or afforded the opportunity to rebuild air before checking the abs lamps, there would not have been a malfunction lamp illuminated.

This is of high importance regarding the fact that a inspector might facilitate the fault to an abs system during the inspection process due to low air pressure and/or not rebuilding air before checking the abs system. Although not all manufacturers are the same in their design it would be prudent if a policy is instituted to ensure that air pressure is verified and at an acceptable psi before checking the abs system. This should cover any ABS system installed and would eliminate inspection related abs faults.

Respectively recommend that any ABS inspection bulletins and any other language pertaining to ABS inspection procedures will be updated and reference that the air system has at least 60 psi of air or be at normal operating air pressure while performing the abs checks.