Test Step 1. Inspect Electrical Connectors and Wiring -807640579

401

TM 9-2320-312-24-2

Troubleshooting Section

Test Step 1. Inspect Electrical Connectors

and Wiring.

g00649124

Illustration 176

Terminal locations for ECM

A. Thoroughly inspect ECM vehicle harness

Results:

connector J1/P1, the firewall bulkhead connector,

OK Proceed to Test Step 2.

and the terminals for the tachometer in the

connectors. Refer to Troubleshooting, "Electrical

Not OK

Connectors - Inspect" for details.

B. Perform a 45 N (10 lb) pull test on each of the

Repair: Perform the following repair:

wires in the ECM connector that are associated

with the terminals for the tachometer:

1. Repair the connectors or wiring and/or replace

the connectors or wiring. Ensure that all of the

P1:38

seals are properly in place and ensure that the

connectors are completely coupled.

P1:39

2. Verify that the repair eliminates the problem.

Refer to Illustration 176.

STOP.

C. Check the ECM connector (allen head screw) for

Test Step 2. Check the ECM Connection

the proper torque of 6.0 Nm (55 lb in).

to the Tachometer.

D. Check the harness and wiring for abrasion and

pinch points from the battery to the ECM.

A. Inspect ECM connector J1/P1. Verify that the

connections are present at P1:39 Tachometer-

Expected Result:

and/or P1:38 Tachometer+.

All connectors, pins and sockets should be

Note: Some of the tachometers require only one

completely coupled and/or inserted and the harness

signal line to be connected. Either of the ECM

and wiring should be free of corrosion, abrasion

terminals can be used for this type of tachometer.

or pinch points.

The other wire should be left disconnected. If both

wires are connected, and one indicates an open

circuit, repair this line.