General Information
21
Pretest Procedures
Step Procedure
M 1. VehicleIgnition:Key-OFF.
2. Measure the resistance across pins 4 and 9 (J1939 High to Ground).
3. Measure the resistance across pins 5 and 9 (J1939 Low to Ground).
a. Iftheresistanceisgreaterthan100Kohmsoropen(InniteResistance).
i. Test Complete.
b. Iftheresistanceisbetween0to100Kohms.
i. Test Failed. Check for shorted connections in the vehicle's J1939 data link harness.
Unplug all J1939 data link components from the data link to isolate a potential
defective component. (See Note)
Note: Refer to vehicle OEM repair manual or contact the OEM for more information on the J1939 data link harness.