Scania EMS DTC 641 Cylinder balancing (min or max), cylinder 7

EMS Engine Management System · Scania

Code 641 (decimal). Some diagnostic tools show it in hexadecimal as 0281.

In short

The cylinder balancing values have reached their maximum or minimum permissible limit.

Applies to: EMS S7EMS S8

What does Scania EMS fault code 641 mean?

The cylinder balancing values have reached their maximum or minimum permissible limit.

What causes Scania DTC 641?

Crankshaft acceleration after combustion in one cylinder is deviating from the average of all cylinders. This may be because: - Leaking injector. - Blocked injector. - Compression too low. - Leakage in the high pressure which affects pressure in the fuel manifold, which can result in fault codes related to cylinder balancing. - Poor combustion, which leads to a different amount of torque in different cylinders. This may have been caused by poor air supply to the cylinder.

How does the system react?

The engine runs unevenly. If the engine receives too much fuel this results in black smoke and if the engine receives too little fuel this results in white smoke.

How to fix Scania EMS fault code 641?

  1. Run Safety precautions for the fuel system.
  2. Check the injector and cylinder compression.
  3. Check the high pressure system for leaks, especially if the fault code has recently been active on more than one cylinder.
  4. Leaks occur most frequently in the pipe connections between the high pressure pump and fuel manifold or fuel manifold and injectors.
  5. Verification Verification can only be carried out if:
  6. No fault code related to the coolant temperature is active.
  7. The engine is idling in neutral gear with the clutch released.
  8. The coolant temperature is approximately 80°C.
  9. Wait up to 30 seconds with the engine idling for the fault code to be deactivated.

This information is for guidance only. Always follow the manufacturer workshop manual and safety procedures; if in doubt, contact an authorised workshop.

Code 641 in other Scania systems

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