DTC P1259: VTEC System Malfunction (2002-2003 models)

Special Tools Required 

• Pressure gauge adapter 07NAJ-P07010A
• A/T low pressure gauge w/panel 07406-0070300
• A/T pressure hose 07406-0020201
• A/T pressure hose, 2,210 mm 07MAJ-PY4011A
• A/T pressure adaptor 07MAJ-PY40120
• Oil pressure hose 07ZAJ-S5A0200

1. Reset the ECM/PCM (see ECM/PCM RESET (2002-2004 MODELS) ).
2. Check the engine oil level, and refill if necessary. Check for external damage to the oil pan (K20A3 engine).
3. Start the engine. Hold the engine speed at 3,000 RPM without load (in Park or neutral) until the radiator fan comes on.
4. Road test the vehicle:

   Accelerate in 1st gear to an engine speed over 5,000 RPM. Hold that engine speed for at least 2 seconds. If DTC P1259 is not repeated during the first road test, repeat this test two more times.

   Is DTC P1259 indicated? 

   1. YES -  Go to step 5.
   2. NO -  Intermittent failure, system is OK at this time. Check the oil consumption if oil was added in step  2. Check for poor connections or loose terminals at the rocker arm oil control solenoid (VTEC solenoid valve), the rocker arm oil pressure switch (VTEC oil pressure switch), and the ECM/PCM.
5. Turn the ignition switch OFF.
6. Disconnect the rocker arm oil pressure switch (VTEC oil pressure switch) 2P connector.
7. Check the rocker arm oil pressure switch (VTEC oil pressure switch) for continuity between rocker arm oil pressure switch (VTEC oil pressure switch) 2P connector terminals No. 1 and No. 2.
   Fig 1: Checking Continuity Between Rocker Arm Oil Pressure Switch 2P Connector Terminals No 1 And No 2

   Courtesy of AMERICAN HONDA MOTOR CO., INC.

   Is there continuity? 

   1. YES -  Go to step 8.
   2. NO -  Replace the rocker arm oil pressure switch (VTEC oil pressure switch) (see ROCKER ARM OIL CONTROL SOLENOID (VTEC SOLENOID VALVE) ASSEMBLY REMOVAL/INSTALLATION  ).
8. Turn the ignition switch ON (II).
9. Measure voltage between rocker arm oil pressure switch (VTEC oil pressure switch) 2P connector terminal No. 1 and body ground.
   Fig 2: Measuring Voltage Between Rocker Arm Oil Pressure Switch 2P Connector Terminal No 1 And Body Ground

   Courtesy of AMERICAN HONDA MOTOR CO., INC.

   Is there battery voltage? 

   1. YES -  Go to step  14.
   2. NO -  Go to step 10.
10. Measure voltage between ECM/PCM connector terminal B9 and body ground.
    Fig 3: Measuring Voltage Between ECM/PCM Connector Terminal B9 And Body Ground

    Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    1. YES -  Repair open in the wire between the rocker arm oil pressure switch (VTEC oil pressure switch) and the ECM/PCM (B9).
    2. NO -  Go to step 11.
11. Turn the ignition switch OFF.
12. Disconnect ECM/PCM connector B (24P).
13. Check for continuity between ECM/PCM connector terminal B9 and body ground.
    Fig 4: Checking Continuity Between ECM/PCM Connector Terminal B9 And Body Ground

    Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    1. YES -  Repair short in the wire between the rocker arm oil pressure switch (VTEC oil pressure switch) and the ECM/PCM (B9).
    2. NO -  Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM (see HOW TO UPDATE THE ECM/PCM ), then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM (see ECM/PCM REPLACEMENT ).
14. Measure voltage between rocker arm oil pressure switch (VTEC oil pressure switch) 2P connector terminals No. 1 and No. 2.
    Fig 5: Measuring Voltage Between Rocker Arm Oil Pressure Switch 2P Connector Terminals No 1 And No 2

    Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    1. YES -  Go to step 15.
    2. NO -  Repair open in the wire between the rocker arm oil pressure switch (VTEC oil pressure switch) and G101.
15. Turn the ignition switch OFF.
16. Disconnect the rocker arm oil control solenoid (VTEC solenoid valve) 2P connector.
17. Check for resistance between rocker arm oil control solenoid (VTEC solenoid valve) 2P connector terminals No. 1 and No. 2.
    Fig 6: Checking Resistance Between Rocker Arm Oil Control Solenoid 2P Connector Terminals No 1 And No 2

    Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there 14-30 Ω ? 

    1. YES -  Go to step 18.
    2. NO -  Replace the rocker arm oil control solenoid (VTEC solenoid valve) (see ROCKER ARM OIL CONTROL SOLENOID (VTEC SOLENOID VALVE) ASSEMBLY REMOVAL/INSTALLATION  ).
18. Remove the rocker arm oil pressure switch (VTEC oil pressure switch) (A) and install the special tools as shown, then reinstall the rocker arm oil pressure switch (VTEC oil pressure switch).
    Fig 7: Removing Rocker Arm Oil Pressure Switch (VTEC Oil Pressure Switch)

    Courtesy of AMERICAN HONDA MOTOR CO., INC.
19. Reconnect the rocker arm oil control solenoid (VTEC solenoid valve) 2P connector and rocker arm oil pressure switch (VTEC oil pressure switch) 2P connector.
20. Connect a tachometer, a scan tool, or the HDS.
21. Start the engine. Hold the engine speed at 3,000 RPM without load (in Park or neutral) until the radiator fan comes on.
22. Check the oil pressure at engine speed of 1,000 and 2,000 RPM. Keep the measuring time as short as possible (less than 1 minute) because the engine is running without load.

    Is the oil pressure below 49 kPa (0.5 kgf/cm ²  , 7 psi)? 

    1. YES -  Go to step 23.
    2. NO -  Inspect the rocker arm oil control solenoid (VTEC solenoid valve) (see CMP SENSOR A REPLACEMENT  ) and the rocker arm oil control solenoid (VTEC solenoid valve) filter (see ROCKER ARM OIL CONTROL SOLENOID (VTEC SOLENOID VALVE) ASSEMBLY REMOVAL/INSTALLATION  ).
23. Turn the ignition switch OFF.
24. Disconnect the rocker arm oil control solenoid (VTEC solenoid valve) 2P connector.
25. Attach the battery positive terminal to rocker arm oil control solenoid (VTEC solenoid valve) 2P connector terminal No. 2.
26. Start the engine, then connect the battery negative terminal to rocker arm oil control solenoid (VTEC solenoid valve) 2P connector terminal No. 1, and check the oil pressure at an engine speed of 3,000 RPM.

    Is the oil pressure above 390 kPa (4.0 kgf/cm ²  , 57 psi)? 

    1. YES -  Go to step 27.
    2. NO -  Inspect the rocker arm oil control solenoid (VTEC solenoid valve) (see CMP SENSOR A REPLACEMENT  ).
27. With the battery terminals still connected to the rocker arm oil control solenoid (VTEC solenoid valve) connector, measure voltage between ECM/PCM connector terminal B9 and body ground.
    Fig 8: Measuring Voltage Between ECM/PCM Connector Terminal B9 And Body Ground

    Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage above 4,000 RPM? 

    1. YES -  Go to step 28.
    2. NO -  Replace the rocker arm oil pressure switch (VTEC oil pressure switch) (see ROCKER ARM OIL CONTROL SOLENOID (VTEC SOLENOID VALVE) ASSEMBLY REMOVAL/INSTALLATION  ).
28. Turn the ignition switch OFF.
29. Disconnect the battery terminals from the rocker arm oil control solenoid (VTEC solenoid valve) terminal connector.
30. Disconnect ECM/PCM connector B (24P).
31. Check for continuity between ECM/PCM connector terminal B15 and body ground.
    Fig 9: Checking Continuity Between ECM/PCM Connector Terminal B15 And Body Ground

    Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    1. YES -  Repair short in the wire between the rocker arm oil control solenoid (VTEC solenoid valve) and the ECM/PCM (B15).
    2. NO -  Go to step 32.
32. Connect rocker arm oil control solenoid (VTEC solenoid valve) 2P connector terminal No. 2 to body ground with a jumper wire.
    Fig 10: Connecting Rocker Arm Oil Control Solenoid 2P Connector Terminal No 2 To Body Ground

    Courtesy of AMERICAN HONDA MOTOR CO., INC.
33. Check for continuity between ECM/PCM connector terminal B15 and body ground.
    Fig 11: Checking Continuity Between ECM/PCM Connector Terminal B15 And Body Ground

    Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    1. YES -  Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM (see HOW TO UPDATE THE ECM/PCM ), then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM (see ECM/PCM REPLACEMENT ).
    2. NO -  Repair open in the wire between the rocker arm oil control solenoid (VTEC solenoid valve) and the ECM/PCM (B15).