Tank fill level, plausibility

A system test is only recommended if the fault has been stored at least three times.

Condition for setting fault

• After refuelling, the DME stores the tank fill level.
  
• During subsequent operation, the consumption is determined on the basis of the amount injection rate
  
• If there is a difference of more than 5 litres compared to the fuel gauge after a computed consumption of 20 litres, this fault is stored.
  
• The fault remains in the status ”currently present” at least until the next refuelling and a fuel consumption of 20 litre create a match between the fuel gauge and DME.
  

System test, fuel gauge sensor

• The fuel tank must be at least 3/4 full
  
• Display the individual fill levels in the control unit functions
  
• Empty the fuel tank and observe the individual fill levels
  
• When one tank chamber has been emptied, start the engine so that the suction-jet pump inside the tank can deliver from one chamber into the other chamber
  
• Refill the fuel tank in steps of 5 litres, observing the individual fill levels
  

Causes

• Installation defective in such a way that the fuel gauge sensor is blocked by cables and components on the inside
  
• Bearings hard to move
  
• Deposits