CLAAS 7751h – A15 Engine Module: Injector Circuit Malfunction Cylinder 1

The engine control unit has detected an open circuit in the electronic fuel injector circuit for cylinder 1. This break in the electrical path prevents the injector from receiving the firing signal, resulting in a lack of fuel delivery, incomplete combustion, rough engine running, and misfires.

• Arion 640-510
• Lexion 480-405

1. 1

   Visually inspect the wiring harness and connectors leading to the cylinder 1 injector for chafing, breaks, corrosion, or loose connections

2. 2

   Disconnect and reconnect the electrical connector at the injector and the A15 engine module to ensure pins are clean, straight, and making solid contact

3. 3

   Measure electrical resistance across the cylinder 1 injector terminals using a multimeter; infinite resistance indicates an internal open circuit in the injector coil

4. 4

   Perform a wiring continuity test on both wires between the A15 module and the injector connector with both ends disconnected

5. 5

   Perform a swap test by exchanging the cylinder 1 injector with another cylinder to see if the fault code follows the injector

1. 1

   Prepare machine

   Disconnect the vehicle's battery before starting any electrical repairs. If working on the fuel system, ensure the area is well-ventilated and take precautions against fuel spillage.

2. 2

   Gain access

   Remove engine covers, air intake piping, or other obstructing components to access the fuel injectors and wiring.

3. 3

   Repair wiring harness

   If a break or damage was found during continuity testing, repair the wiring using appropriate connectors and heat shrink tubing to ensure a weather-resistant connection.

4. 4

   Replace fuel injector

   Thoroughly clean the area around the injector. Disconnect the fuel lines and electrical connector, remove the bolt or clamp holding the injector, and carefully extract the old injector (a slide hammer or gentle prying may be necessary if seized). Clean the injector bore, install the new injector with new seals or copper washers, torque the retaining bolt to manufacturer specifications, and reconnect the fuel lines and electrical connector.

5. 5

   Finalize repair

   Reconnect the battery, clear fault codes with a diagnostic tool, start the engine to check for leaks, and perform a final scan to ensure the code does not return.