## Diesel Engine Management System

#### DTC Troubleshooting (cont'd)

11-123

DTC P1378: Glow Time Control Circuit Short

1. Check the ''On Board Diagnostic (OBD) System Check''.

Was the ''OBD System Check'' performed?

YES – Go to step 2.

NO – Go to OBD System Check.

1. Turn the ignition switch ON (II).

Is DTC P1378 indicated?

YES – Go to step 3.

NO – Intermittent failure, system is OK at this time. Check for poor connections or loose wires at the glow relay and at the ECM.

1. Check the glow relay (60A) fuses.

Are fuses OK?

YES – Go to step 4.

NO – Replace the fuse.

1. Turn the ignition switch OFF.

1. Disconnect the ECM connector A.

1. Disconnect the glow relay connector.

1. Check for short to ground in the glow relay circuit between the glow relay connector and the ECM connector A No. 19.

Was a problem found?

YES – Repair short to ground in the wire between the glow relay connector and the ECM connector A terminal No. 19.

NO – Go to step 8.

1. Check connection at the glow relay and replace the terminals if necessary.

Was a problem found?

YES – Replace the terminal.

NO – Go to step 9.

1. Replace the glow relay.

1. Connect the ECM connector A.

1. Turn the ignition switch ON (II).

Is DTC P1378 indicated?

YES – Substitute a known-good ECM and recheck. If symptom/indication goes away, replace the original ECM.

NO – System is OK.

NOTICE

The battery power supply short circuit to 5 V power supply damages the ECM.

a a a