Misfires - fault code description - ME

AD07.61-P-4000-11AA

Misfires - fault code description - ME



Misfire, emission limit

1

Fault code

( Readout on generic scan tool)

P2043 Sum (P0300)

P2044 Misfires on cylinder 1 (P0301)

P2048 Misfires on cylinder 2 (P0302)

P2046 Misfires on cylinder 3 (P0303)

P2045 Misfires on cylinder 4 (P0304)

P2049 Misfires on cylinder 5 (P0305)

P2047 Misfires on cylinder 6 (P0306)

2

Fault storage

Actuation of the engine diagnosis indicator lamp (EURO3/4)

or CHECK ENGINE (MIL) malfunction indicator lamp 

after expiry of test duration and fault

following two successive driving cycles with faults

3

Checking frequency

Continuous

4

Checked signal or status

Number of detected combustion misfires (detection via a smooth operation assessment)

5

Fault setting conditions

Limit value for emission limit

A maximum of 27 combustion misfires within 1000 engine revolutions

 Ultra low emission vehicle: a maximum of 17 combustion misfires within 1000 engine revolutions.

6

Check prerequisites

- engine speed running at approx. 500 to 6250 rpm

- engine speed change less than 1500 rpm per second

- load change less than 50% per second

- no ESP control intervention function

- no road surface irregularities recognized (via CAN by ESP control unit , determined via comparison of wheel speeds)

- no fault in the signal from the camshaft Hall sensor

- no deceleration fuel shutoff

- engine load more than 17%

- sensor wheel adaptation already performed in deceleration phase

7



If too many misfires occur at a cylinder, the cylinder is cut off (cylinder selective fuel cutoff).

Misfires through faults in the ignition system

If ignition does not take place misfiring occurs. If faults on the ignition system are also stored in addition to the misfire faults then begin with troubleshooting in the ignition system.

Maximum permissible deviation from smooth running on a cylinder of approx. 3 ms2.

If this value is exceeded then determine the ignition circuit causing this through switching off the ignition circuit as follows:

1. Switch off an ignition circuit (a or b) using STAR DIAGNOSIS.

2. Observe the smooth running value on the effected cylinder.

- The value only changes by a minimal amount (up to approx. 2 ms2): the ignition circuit which is still switched in is fault-free.

- The value changes strongly (above approx. 2 ms2): the ignition circuit which is still switched in has a fault; check the spark plug, ignition line, ignition coil.

Misfires due to fuel starvation

If combustion misfires are recognized, another fault code P203A (P0460) is output if the level in the fuel tank is too low. This information suggests combustion misfires due to fuel starvation.

Misfiring because of miscellaneous causes

Combustion misfires may be caused by many faults in the injection system. Other component or function faults are usually stored, in addition to the misfire fault, in this case.

The cause may also be due to faults in the engine mechanics.