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 valve cover at test connection of fuel distributor line.
CAUTION: Cap must be used only once!
2. Connect pressure gauge P 378 or VW 1343 with attachment line 9559 and connect to test connection.
3. Remove ECM relay (R53) from fuse/relay panel and connect terminals 30 and 87b with locally manufactured fused jumper cable. Fuel pump must work now.
- Fuel pressure:
- Engine not running: 3.8 +/- 0.2 bar
- Engine at idle: 3.3 +/- 0.2 bar.
Check fuel volume supply.
Diagnostic conditions: If the fuel volume is too low, first check power supply for pump and filter.
1. Remove intercooler and close open tubes.
2. Remove heater blower in left rear engine compartment.
3. Remove fuel return line at fuel pressure regulator while holding line firmly against connector. Catch fuel in suitable container.
4. Install special tool adapter hose 9507, (Ordering No.000.721.950.70). Hold open end in measuring cylinder.
5. Remove ECM relay (R53) from central electric fuse/relay panel and bridge cavities 30 and 87b (markings 3 and 7 on fuse/relay panel) with locally manufactured fused jumper cable. The fuel pump should run now.
- Let fuel run for 30 seconds into a measuring cylinder.
- Fuel volume must be at least 1,100 cm3/30s, meaning that after 30 seconds the measuring cylinder must contain at least 1,100 cm3.
WARNING: Observe all safety precautions when working with fuel.
Check triggering of fuel injectors..
Wiring Diagram.
NOTE: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.
C) Injection end stage (minus supply)
1. Connect adapter cable (Bosch-No.:1 684 463 093) 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 following 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 intake air system for leaks.
1. Remove intake air intercooler and air cleaner.
2. Remove Mass Air Flow Sensor.
3. Remove right side grille.
4. Install sealing cover 9264/1 with bolts M 4 x 40 to Mass Air Flow Sensor.
NOTE: Before tightening the bolts, check positioning of the the sealing cover to the Mass Air Flow Sensor. There must be no light gaps.
5. At right rear wheel well, remove front half of wheel well liner. Close hose of oil reservoir pressure valve with suitable plug.
6. Build up pressure of approx. 0.5 bar.
- With the pressure applied, you should be able to hear major leaks. For smaller leaks use leak spray.
NOTE: Checking for leaks should involve the entire intake air system, the intercooler and the oil reservoir.