CM850 Electronic Control System – FAULT CODE 778

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Overview

Camshaft Engine Position Sensor Circuit SMALL | MEDIUM | LARGE

Circuit Description

The camshaft engine position sensor provides engine position information to the electronic control module (ECM). The sensor is powered by (+) 5-VDC. The sensor generates the signal by sensing the movement of target teeth machined into a tone wheel that is mounted to the camshaft.

Component Location

The camshaft position sensor is located below the fuel pump in the back of the gear housing.

Shop Talk

This fault is recorded when the ECM does not receive a signal from the camshaft position sensor or the signal the ECM receives is degraded.

Possible causes of this fault code include:

• Open circuit on the supply, signal, or return circuits in the sensor, engine harness, or ECM
• Short circuits to ground or return circuits in the sensor, engine harness, or ECM
• Short circuits to voltage source in the sensor, engine harness, or ECM.

INSITE™ electronic service tool monitor parameters associated with this fault code and sensor include:

• Camshaft engine position sensor state
• Damage to the sensor target teeth or tone wheel.

If this fault code occurs intermittently, look closely for causes of intermittent harness connections such as loose or worn pins in the engine harness connectors.

If this fault code occurs intermittently, Fault Code 2322 will also be active or have high counts.

Refer to Troubleshooting Fault Code t05-778