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Home >> Mercedes Benz >> 2001 >> ML430 >> Repair and Diagnosis >> Engine Performance >> Tune-Up >> Mixture Formation - 163 Chassis (3 Of 4) >> Self-Diagnostic System >> ME-SFI fault code description, misfire - AD07.61-P-4000-11A

ME-SFI fault code description, misfire - AD07.61-P-4000-11A

1 Fault code P0300 Misfire, amount
P030I Misfire, cylinder 1
P0302 Misfire, cylinder 2
P0303Misfire, cylinder 3
P0304 Misfire, cylinder 4
P0305Misfire, cylinder 5
P0306Misfire, cylinder 6
P0460 Fuel level too low
P0462 Fuel level too low
2 Error storage after expiry of test duration and fault
Activation of engine diagnostics malfunction indicator lamp (EURO3/4)
or CHECK ENGINE (MIL) USA ONLY
A Misfire (emission level) 
The malfunction indicator lamp is activated after two successive faulty driving cycles
B Misfire "damaging TWC" 
Malfunction indicator lamp immediately activated on case of misfiring
3 Frequency of test Continuously
4 Checked signal or status Number of recognized misfires (detection through smooth operation analysis)
5 Limit values Maximum of 20 misfires within 1000 engine revolutions
Maximum of 4-35 misfires within 200 engine revolutions
(map dependent on engine speed and load; e.g. 4 misfires as from medium engine speed and load, 35 misfires in neutral without load)
6 Test prerequisites
  • Engine speed approx. 450 6000 rpm
  • Engine speed change less than 1900 rpm per second
  • Load change less than 50% per second
  • Engine started up at least 5 s earlier
  • No ESP control intervention function
  • Pulse-generator wheel adaptation in deceleration has taken place
  • No road bumps detected (via CAN by ASR/ESP control module, determined by comparing wheel speeds)

    No fault signal from camshaft Hall sensor

  • No inertia fuel shutoff
7 IMPORTANT If too many misfires occur at a cylinder, the cylinder is cut off (cylinder-selective fuel cutoff).
Misfires caused by ignition system faults 
If ignition does not take place misfiring occurs. If in addition to the misfiring faults ignition system faults are also stored, then start troubleshooting in the ignition system.
Maximum permissible smooth-operation deviation on a cylinder approx. 3 ms 2 .
If this value is exceeded, through switching off the ignition circuit, determine the ignition circuit causing it in the following manner:
  1. Switch off an ignition circuit (a or b) using STAR DIAGNOSIS/HHT.
  2. Observe the smooth operation value at the affected cylinder.
    • Value alters insignificantly (up to approx. 2 ms 2 ): The still switched on ignition circuit is fully operational.
    • Value alters significantly (more than approx. 2 ms 2 ): The still switched on ignition circuit is faulty. Check spark plugs, ignition cable and ignition coil.

Misfiring through fuel starvation 
If misfires are detected, and the fuel level is too low the fault codes P0460 or P0462 are issued.
This information indicates misfiring is occurring due to fuel starvation.
Misfiring because of miscellaneous causes 
Misfiring can be caused by many faults in the injection system. Usually, the misfiring fault is stored along with faults to other components or functions.
Faults in the engine mechanics may also be the cause of misfiring.