019-025   Data Link Circuit, Control

The datalink circuit is located in the sensor wiring harness.

The purpose of this datalink is to allow the ECM to communicate to the vehicle control-operated systems such as the transmission controllers, antislip reduction system, and so on. The J1587 datalink circuit includes the wire connected to pins 10 and 20 in the sensor wiring harness.

Disconnect the sensor harness connector from the ECM. Refer to Procedure

019-043.

CAUTION  To reduce the possibility of connector damage, do not use probes or leads other than Part Number 3822758. The leads must fit tightly in the connector without expanding the pins in the connector.

Insert a test lead into pin 10 of the sensor harness. Connect the alligator clip to the positive (+) multimeter probe. Touch the negative multimeter probe to pin A in the two-way connector. Measure the resistance. The multimeter

must show a closed circuit (10 ohms or less).

Remove the test lead from pin 10 and place it into pin 20 of the connector. Touch the negative multimeter probe to pin B in the two-way connector. Measure the resistance. The multimeter

must show a closed circuit (10 ohms or less).

If more than 10 ohms are measured in either of these steps, there can be an open circuit in pin 10, or pin 20 or the polarity is

not
correct.

If the resistance shows a closed circuit, pins 10 and 20

must still be checked for a short circuit to ground and a short circuit from pin to pin.

Make sure the datalink connector is disconnected from the vehicle wiring harness.

Insert a test lead into pin 10 of the sensor harness connector. Connect the alligator clip to the positive (+) multimeter probe. Touch the negative
(-) multimeter probe to the engine block ground. Measure the resistance. The multimeter

must show an open circuit (more than 100k ohms).

Move the test lead from pin 10 and place it into pin 20 of the sensor connector. Touch the negative (-) multimeter probe to the engine block ground. Measure the resistance. The multimeter

must show an open circuit (more than 100k ohms). If less than 100k ohms are measured in either of the previous steps, there is a short circuit to ground. Repair or replace the sensor harness. Refer to Procedure

019-043.

Make sure the datalink connector is disconnected from the vehicle wiring harness.

Insert a test lead into pin 10 of the sensor harness. Place the other test lead into pin 1 of the sensor harness. Connect the alligator clips to the multimeter probes. Measure the resistance. The multimeter

must
show an open circuit (more than 100k ohms).

Move the test lead from pin 1 and place it into pin 2, then pin 3. The multimeter

must show an open circuit (more than 100k ohms) in all pins.

Move the test lead from pin 10 and place it into pin 20. Place the other test lead into pin 1. Measure the resistance. The multimeter

must
show an open circuit (more than 100k ohms).

Move the test lead from pin 1 and place it into pin 2, then pin 3. The multimeter

must show an open circuit (more than 100k ohms) in all pins. If the circuit is

not open in the previous steps, there is a short circuit between pin 10 or pin 20 and any pin that measured less than 100k ohms. Repair or replace the sensor harness. Refer to Procedure

019-043.

Connect all components when the repair is complete.