12
Pretest Procedures
Step Procedure
D 1. VehicleIgnition:Key-ON,Engine-OFF.
2. Measure for J1939 data voltage on pins 7 and 5 of the DIU harness connector.
(J1939 High to Ground)
a. If the voltage is fluctuating between 2 to 5 volts.
i. Proceed to Step E.
b. If the voltage is a constant at 0 volts.
i. TestFailed.Checkforopen/looseconnectionsinthevehicle’sJ1939datalinkharness.
(See Note)
Note: Refer to vehicle OEM repair manual or contact the OEM for more information on the J1939 data link harness.
Pin #Description
J1-5 Chassis Ground
J1-7 J1939+
7
Chassis
Ground
5
J1939-
J1939+