What is SPN 791:
SPN 791 refers to a problem with the Engine Speed Sensor Circuit, which is sending an incorrect signal to the ECM. This can lead to issues such as poor engine performance, incorrect fuel delivery, or difficulty in engine starting.
Why This Happens:
- Faulty engine speed sensor.
- Damaged or shorted wiring in the sensor circuit.
- Loose or corroded sensor connectors.
- ECM misinterpretation of sensor data.
- Signal interference or external damage to the sensor.
How to Fix It:
- Inspect the engine speed sensor for damage or malfunction.
- Check the wiring and connectors for damage or corrosion.
- Test the sensor’s signal to ensure it matches manufacturer specifications.
- Replace the faulty sensor if it does not meet specifications.
- Ensure the ECM is properly communicating with the sensor.
How to Avoid It Before It Happens:
- Perform regular checks on the engine speed sensor and wiing.
- Keep connectors clean and free from corrosion or moisture.
- Test sensor performance periodically to detect potential issues.
- Inspect ECM communication pathways for any interference or faults.
- Clue’s Fleet Management services help monitor engine systems and detect sensor performance issues early.
