P0300
P0300
Misfire recognized
P0301
Cylinder 1 - Misfire detected
P0302
Cylinder 2 - Misfire detected
P0303
Cylinder 3 - Misfire detected
P0304
Cylinder 4 - Misfire detected
P0305
Cylinder 5 - Misfire detected
P0306
Cylinder 6 - Misfire detected
P1585
Misfire with empty fuel tank
Function
To detect misfire, the decrease of engine speed is evaluated when no combustion occurs at one or more cylinders.
Faults that are emission related and faults that are damaging to the Three Way Catalytic Converter (TWC) are separate categories.
The engine speed is measured with an inductive sensor that is located above the ring gear of the flywheel.
The ring gear is divides into three segments. For the detection, the difference is calculated by the time measured between the segments. This difference is corrected by a mean value that is developed over several segments to compensate for the engine speed fluctuations caused by driving conditions. If the corrected value is above a specified value which depends on engine speed and engine load, a misfire is detected.
Diagnostic conditions
A cycle of 1,000 crank shaft revolutions each is evaluated (for misfire damaging to the TWC, 200 crank shaft revolutions). The misfire occurrences are compared to a threshold value. If the number of misfire is larger than the threshold value, a fault is recorded in memory.
The Malfunction Indicator Lamp (MIL) is switched on and stays on, when the misfire rate is above the threshold value for two consecutive driving cycles, when the FTP-limit values are exceeded by 1.5 times.
The MIL blinks during a time when the misfire rate can be damaging to the TWC. If the misfire rate is no longer reaching the threshold, the MIL goes back to constant on.
NOTE:
- When the fuel tank is driven to empty, misfire can occur. For this reason the fuel level in the tank is also stored in memory. If the tank was empty, there was probably no fault. Erase DTC memory and road test vehicle. DTC P1585 is displayed as from program version 14 and can be read only by means of a scan tool. The tank content (full or empty) is stored under the ambient conditions with the system tester.
- Short circuits to B+ or ground of the Oxygen Sensors (H02S) ahead of the TWC cause the mixture to be too rich or too lean. This can cause misfiring. If an additional DTC for an H0S2 ahead of the TWC is stored in memory, first correct this fault and road test vehicle.
Wiring Diagram
Diagnostic procedure
Test requirements: Engine mechanically OK
Check fuel pressure
1. Remove heater blower at the rear left of the engine compartment.
2. Remove valve cover at test connection of fuel distributor line. Tightening torque: 2.5 + 0.5 Nm
NOTE: Cover must be used only once.
3. Connect pressure gauge P 378 or VW 1318 with attachment line 9559 and connect to test connection.
4. Remove ECM relay (R53) from fuse/relay panel and connect terminals 30 and 87b with locally manufactured fused jumper cable and trigger fuel pump with system tester. Fuel pump must work now.
5. Test values:
Engine not running: 3.8 +/- 0.2 bar
Engine at idle: 3.3 +/- 0.2 bar
Check volume supply of fuel pump.
1. Remove heater fan at rear left of engine compartment.
2. Remove fuel return line at fuel pressure regulator, making sure that you counter when you do this. Collect remaining fuel.
3. Connect special tool hose 9507, (Order No. 000.721.950.70) to pressure regulator and hold in a measuring vessel.
4. Disconnect ECM relay (R53) from fuse/relay panel and connect terminals 30 and 87 b (labeled 3 and 7 on fuse/relay panel) with locally manufactured fused jumper cable and trigger fuel pump with system tester. The fuel pump must work now.
5. Allow fuel to flow into a measuring vessel. Fuel volume supply must be at least 850 cm3/30s, i.e. after these 30 seconds, the measuring vessel must contain at least 850 cm3 fuel.
WARNING: Observe the safety regulations under all circumstances.
Check triggering of fuel injectors.
The fuel injectors can be triggered one by one with system tester 9288 in menu point "output check'. The opening of the fuel injectors is however difficult to hear (muffled). If no pulse is audible, check triggering as follows:
A) Voltage supply
1. Remove connector of fuel injector to be checked.
2. Connect voltmeter between injector connector, cavity 2 and ground.
3. Switch ignition on.
- Specified value: battery voltage. If meter does not read battery voltage, check wiring according to wiring diagram for continuity or short circuit.
B) Coil resistance of fuel injectors
1. Remove connector of fuel injector to be checked.
2. With ohmmeter, measure resistance between terminals of fuel injector. Specified value: 15 - 17 Ohms
B) Injection end stage (minus supply)
1. Connect special tool VAG 1315 A/1 between fuel injector and connector.
2. Connect engine tester according to manufacturer's instructions. Connect tester cable with adapter cable.
CAUTION: Tester cables must not contain ground connections.
3. Start engine: For a perfectly working injector end-stage, the above display must be shown at starting rpm.
NOTE: If the engine does not start, or if the idling speed drops, replace tester cable at adapter cable.
Check air intake system for leaks.
1. Remove air cleaner cover and insert.
2. Undo hose clamp on mass air flow sensor with a cross-head screwdriver, e.g. from Messrs. With Order No. 153-1(350 mm long).
3. The restricted space available necessitates separation of the mass air flow sensor and air cleaner housing in the engine compartment. To remove, turn the mass air flow sensor in the direction of the arrow (driving direction), at the same time countering at the air cleaner housing (bayonet lock).
4. Lever off circlip and remove protective grille.
5. Secure sealing plate 9264/1 on mass air flow sensor using screws M 4 x 40 and washers.
NOTE: Check the position of the mass air flow sensor on the sealing plate before finally tightening the screws, i.e. no light gap must be visible upon inspection.
6. Build up a pressure of approx. 0.5 bar. Large leaks are very audible when the pressure has been built up; small leaks can be made visible using leak spray.
NOTE: The pressure relief valve on the oil tank opens at 180 +/- 20 mbar. Block the valve. To do this, remove the front wheel housing liner of the right rear wheel housing. Close off the hose from the oil tank pressure relief valve with a suitable stopper.
- Remove the stopper from the hose after carrying out the leak test.
- Assemble the mass air flow sensor and air cleaner housing in the engine compartment before attaching the mass air flow sensor to the air intake system.