Electronic Control System ISM and QSM11 Engines – FAULT CODE 315

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Overview

Injector Circuit SMALL | MEDIUM | LARGE

Circuit Description

The injector solenoid valves are actuated by the electronic control module (ECM) to control fuel metering and timing. Each injector solenoid is connected to the ECM by a supply and a return wire. An electrical pulse is sent to the injector from the ECM on the supply wire and returns to the ECM on the return wire after actuating the solenoid. Each solenoid valve is normally open, and it is only closed by an electrical pulse from the ECM during fuel injection and metering.

Component Location

There are two pieces to an ISM and QSM actuator harness – one internal and the other external. The external portion of the actuator harness extends from the connector port in the ECM to the backside of the rocker lever housing. The external harness connects to the internal harness with a 15-pin connector at the backside of the rocker lever housing. The internal actuator harness runs along the inside of the rocker lever housing on the right side. It has six connectors spaced along its length – one for each injector solenoid. These connectors attach to the pigtail connector on each injector.

Shop Talk

Possible causes for this fault code include low injector solenoid resistance, a short to battery voltage, and a short between injector solenoid wires.

Refer to Troubleshooting Fault Code t05-315