Electronic Control System Signature, ISX and QSX15 Engines – 019-043   Engine Wiring Harness

The Signature, ISX and QSX15 engines use separate wiring harnesses to control the engine and some vehicle operations. There are three connectors for the wiring harnesses. In the picture shown, the following harnesses connect to the ECM from right to left:

1. Sensor harness
2. Actuator harness
3. OEM harness.

Disconnect the harness from the sensors and switches.

1. Intake manifold pressure/temperature sensor
2. Crankshaft or camshaft position sensor
3. Coolant temperature sensor
4. Front and rear rail pressure sensor
5. Fuel shutoff solenoid
6. Fuel pressure sensor
7. 8-pin pass-through connector

1. Centinel™ connector (if equipped)
2. Ambient air pressure sensor
3. Oil pressure/temperature sensor
4. Wet tank pressure sensor
5. Water-in-fuel sensor
6. Wastegate controller
7. Fuel inlet restriction sensor ( if equipped).

Disconnect the 31-pin Deutsch connector from the OEM side of the wiring harness.

Remove the harness clamps from the support bracket of the engine block.

Disconnect the engine harnesses from the ECM.

Replace or repair the engine harness if there is an open circuit or a short circuit found under the protective covering of the harness body.

Connect the engine harnesses to the ECM.

Connect the harnesses to the sensors and switches.

1. Intake manifold pressure/temperature sensor
2. Crankshaft or camshaft position sensor
3. Coolant temperature sensor
4. Front and rear rail pressure sensor
5. Fuel shutoff solenoid
6. 8-pin pass-through connector
7. Fuel pressure sensor

1. Centinel™ connector (if equipped)
2. Ambient air pressure sensor
3. Oil pressure/temperature sensor
4. Wet tank pressure sensor
5. Water-in-fuel sensor
6. Wastegate controller
7. Fuel inlet restriction sensor (if equipped).

Connect the 31-pin Deutsch connector to the engine harness.

Install the harness clamps that hold the engine harness to the block.