DTC Troubleshooting: P0300 and P0301, P0302, P0303, P0304 (European M/T)

DTC Troubleshooting: P0300 and P0301, P0302, P0303, P0304

DTC P0300:	Random Misfire and Any Combination of the Following:
DTC P0301:	No. 1 Cylinder Misfire
DTC P0302:	No. 2 Cylinder Misfire
DTC P0303:	No. 3 Cylinder Misfire
DTC P0304:	No. 4 Cylinder Misfire

Special Tools Required
Oil Pressure gauge attachment ( 07NAJ-P070100)

Low pressure gauge ( 07406-0070001)

Hose oil pressure ( 07ZAJ-S5A0200)

NOTE:

If the misfire is frequent enough to trigger detection of increased emissions during 2 consecutive driving cycles, the MIL will come on, and DTC P0300 (and some combination of P0301 through P0304) will be stored.
If the misfire is frequent enough to damage the catalyst, the MIL will blink whenever the misfire occurs, and DTC P0300 (and some combination of P0301 through P0304) will be stored. When the misfire stops, the MIL will remain on.
Troubleshoot the following DTCs first if any of them were stored along with the random misfire DTC(s):

P0107, P0108: Manifold absolute pressure (MAP) sensor
P0171, P0172: Fuel system
P0335, P0339: Crankshaft position (CKP) sensor
P0365, P0369: Camshaft position (CMP) sensor
P0511: Idle air control (IAC) valve

1.	Note the following freeze data. Engine speed Vehicle speed Throttle position CLV Gear position

2.	Do the DTC CLEAR in the CLEAR MENU with the Honda PGM Tester or the HDS.

3.	Start the engine with no load (in Park or neutral), then let it idle.

Monitor the OBD STATUS for DTC P0301, P0302 P0303, or P0304 in the DTCs MENU with the Honda PGM Tester or the HDS.

Is it FAILED?

YES - Go to 9.

NO - If it is PASSED, go to 5. If it is EXECUTING, keep the driving condition continually until a result comes on. If it is Out of CONDITION, wait for several minutes, and recheck.

5.	Check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE and/or CYL4 MISFIRE in the DATA LIST for 10 minutes with the Honda PGM Tester or the HDS. Does CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE and/or CYL4 MISFIRE show misfire counts? YES - Go to 9. NO - Go to 6.

6.	Test-drive the vehicle for several minutes in the range of the recorded freeze data.

Monitor the OBD STATUS for DTC P0301, P0302 P0303, or P0304 in the DTCs MENU with the Honda PGM Tester or the HDS.

Is it FAILED?

YES - Go to 9.

NO - If it is PASSED, go to 8. If it is EXECUTING, keep the driving condition continually until a result comes on. If it is Out of CONDITION, go to 6. and recheck.

Check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE and/or CYL4 MISFIRE in the DATA LIST for 10 minutes with the Honda PGM Tester or the HDS.

Does CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE and/or CYL4 MISFIRE show misfire counts?

YES - Go to 9.

NO - Intermittent failure, system is OK at this time.n

9.	Turn the ignition switch OFF.

10.	Check fuel quality. Is the quality good? YES - Go to 11. NO - Drain the fuel from the fuel tank, and fill with known-good fuel, then go to 20.

11.	Clean the all spark plugs .

12.	Test-drive the vehicle for several minutes in the range of the recorded freeze data.

13.	Check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE and/or CYL4 MISFIRE in the DATA LIST for 10 minutes with the Honda PGM Tester or the HDS. Does CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE and/or CYL4 MISFIRE show misfire counts? YES - Go to 14. NO - Go to 20.

14.

Check the fuel pressure.

Is the fuel pressure OK?

YES - Go to 15.

NO -

If the pressure is too high, replace the fuel pressure regulator, then go to 20.
If the pressure is too low, check the fuel pump, the fuel feed pipe, and the fuel filter. If they are OK, replace the fuel pressure regulator, then go to 20.

15.	Turn the ignition switch OFF.

16.	Remove the VTEC oil pressure switch (A) or the belt and install the special tools as shown, then install the VTEC oil pressure switch (A) or the belt in the pressure gauge adapter (B). NOTE: Install the part in the reverse order of removal with a new O-ring.

17.	Reconnect the VTEC oil pressure switch 2P connector.

18.	Start the engine. Hold the engine at 3,000 rpm (min^-1) with no load (in Park or neutral) until the radiator fan comes on.

19.

Check the oil pressure at engine speeds of 1,000 and 2,000 rpm (min^-1). Keep the test time as short as possible (less than 1 minute) because the engine is running with no load.

Is the oil pressure below 49 kPa (0.5 kgf / cm², 7psi)?

YES - Check for air in the fuel line, then go to 20.

NO - Inspect the VTEC system oil line, then, go to 20.

20.	Turn the ignition switch ON (II).

21.	Do the ECM/PCM RESET in the CLEAR MENU with the Honda PGM Tester or the HDS.

22.	Do the CKP PATTERN CLEAR in the CLEAR MENU with the Honda PGM Tester or the HDS.

23.	Do the ECM/PCM idle learn procedure.

24.	Do the CKP pattern learn procedure.

25.	Test-drive the vehicle for several minutes in the range of the recorded freeze data.

26.

Check for Temporary DTCs or DTCs in the DTCs MENU with the Honda PGM Tester or the HDS.

Are any Temporary DTCs or DTCs indicated?

YES - If DTC P0300, P0301, P0302, P0303 or P0304 are indicated, check for poor connections or loose terminals at the ignition coil, the injector, and the ECM/PCM, then go to troubleshooting DTC P0301, P0302, P0303 or P0304. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC troubleshooting.

NO - Go to 27.

27.

Monitor the OBD STATUS for DTC P0301, P0302, P0303 or P0304 in the DTCs MENU with the Honda PGM Tester or the HDS.

Is it PASSED?

YES - Troubleshooting is complete.n

NO - If it is FAILED, then go to 1. and recheck. If it is EXECUTING, keep the driving condition continually until a result comes on. If it is Out of CONDITION, go to 25 and recheck.