Bendix Commercial Vehicle Systems VORAD VS-400 INSTALLATION NOTES - Manual (Page 45)

General Information
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Appendix 4A
4. Component Power Supply Test
Overview
The base Bendix ™ VORAD ® VS-400 system consists of two components, the FLR and DIU . Both should be powered by the main ignition
power supply (12 Vdc) . If one of these components is incorrectly connected to constant battery power or a secondary ignition source other
than the main ignition power supply bus, there is the potential for J1939 communication Diagnostic Trouble Code (DTC) between the FLR
and the DIU . These include, but are not limited to, Diagnostic Trouble Codes (DTCs) 32 and 33 . If these Diagnostic Trouble Codes (DTCs)
appear after the installation of a new VS-400 system or if the system is suspected of having this problem, perform this test to verify proper
ignition power source to the FLR and the DIU .
Verifying Ignition Power to the DIU
Step Procedure
A 1. Vehicle Ignition: Key-OFF, Engine-OFF.
2 . Disconnect the 8-way connector from the back of the VS-400 Driver Interface Unit (DIU) .
3 . Measure for zero voltage on pins 4 and 5 on the harness connector .
a . If the voltage is 0 .5 volts or less .
i . Proceed to Step B .
b . If voltage is greater than 0 .5 volts but less than battery voltage .
i . Test Failed . Check DIU power supply wiring for sources of stray voltage or shorts to voltage .
c . If the voltage is within 0 .6 volts of the battery voltage measured in Step A .
i . Test Failed . The DIU is improperly wired or shorted to a battery power source . Correct the
wiring by connecting the DIU to the main ignition power supply bus and repeat Step .