E39 / P0304 00
Read the instructions below then
start the fault diagnostic procedure.
Symptom: CHECK ENGINE
(Check Engine lamp flashes if diagnostics has detected a misfire that is harmful to the catalytic converter).
Uneven running and misfiring.
Cylinder 4 Misfire Detected.
Fault symptom
CHECK ENGINE
(Check Engine lamp flashes if diagnostics has detected a misfire that is harmful to the catalytic converter).
Uneven running and misfiring.
On-board diagnosis
Type of diagnosis:
| Each misfire is registered and evaluated two different ways depending on the type of misfire. |
| • | Harmful to the catalytic converter. |
Enable criteria:
| General conditions for this DTC |
| • | Positive engine torque (negative torque = engine braking). |
| • | Engine temperature above -7°C. |
| • | The following diagnostic trouble codes may not be generated: |
| P0010, P0011, P0013, P0014 |
| P0111, P0112, P0113, P0114 |
| P0122, P0123, P0222, P0223 |
| P0116, P0117, P0118, P0119 |
Fault criteria:
| The control module has detected a too large variation in the crankshaft's rotation speed. |
Checking the wiring harness
Jiggle the wiring harness at several points to detect intermittent breaks or short circuits. Check also the connector for oxidation or loose pins.
Diagnostic help
Diagnosis regards:
| Fuel/air mixture too rich or too lean, insufficient compression, poor spark plugs causing incomplete combustion. |
| A cursory check is carried out on connectors and hoses. Then a through check is carried out on compression, ignition timing and fuel system. |
Functions in the diagnostic tool related to the fault:
| • | Airmass Deviation from Calculated |
| • | Requested Fuel Rail Pressure |
| (See also description of readings/activations in diagnostic tool) |
