## Diesel Engine Management System

#### DTC Troubleshooting (cont'd)

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DTC P0118: ECT Sensor Circuit High Voltage

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).

1. Check the ECT with the scan tool.

Is about 215°C (419°F) indicated?

YES – Go to step 4.

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

1. Turn the ignition switch OFF.

1. Disconnect the ECT sensor 2P connector.

1. Connect the ECT sensor 2P connector terminals No. 1 and No. 2 with a jumper wire.

Wire side of female terminals

Injector 2P connector

JUMPER WIRE

1. Turn the ignition switch ON (II).

1. Check the ECT with the scan tool.

Is about 140°C (284°F) indicated?

YES – Replace the ECT sensor.

NO – Go to step 9.

1. Turn the ignition switch OFF.

1. Disconnect ECM connector.

1. Check the ECT sensor circuit for an open.

Wire side of female terminals

ECT sensor 2P connector

JUMPER WIRE

Is a problem found?

YES – Repair the ECT open circuit.

NO – Substitute a known-good ECM and recheck. If symptom/indication goes away, replace the original ECM.

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