DTC P1259: VTEC System Malfunction

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 adapter 07MAJ-PY40120
• Oil pressure hose 07ZAJ-S5AA200

1. Reset the ECM/PCM (see HOW TO RESET THE ECM/PCM ).
2. Check the engine oil level, and refill if necessary. Check for external damage to the oil pan.
3. Start the engine. Hold the engine at 3,000 RPM with no 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 4,000 RPM. Hold the speed for at least 2 seconds. If DTC P1259 is not repeated during the first road test, repeat the 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 VTEC solenoid valve, VTEC oil pressure switch, and at the ECM/PCM.
5. Turn the ignition switch OFF.
6. Disconnect the VTEC oil pressure switch 2P connector.
7. Check for continuity between VTEC oil pressure switch 2P connector terminals No. 1 and No. 2.
   Fig 1: Checking Continuity Between VTEC Oil Pressure Switch 2-Pin Connector Terminals No. 1 & No. 2

   Courtesy of AMERICAN HONDA MOTOR CO., INC.

   Is there continuity? 

   1. YES  - Go to step 8.
   2. NO  - Replace the VTEC oil pressure switch.
8. Turn the ignition switch ON (II).
9. Measure voltage between VTEC oil pressure switch 2P connector terminal No. 1 and body ground.
   Fig 2: Measuring Voltage Between VTEC Oil Pressure Switch 2-Pin Connector Terminal No. 1 & 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 & Body Ground

    Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    1. YES  - Repair open in the wire between the 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 & Body Ground

    Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    1. YES  - Repair short in the wire between the 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, then recheck (see ECM/PCM UPDATING AND SUBSTITUTION FOR TESTING ). If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM.
14. Measure voltage between VTEC oil pressure switch 2P connector terminals No. 1 and No. 2.
    Fig 5: Measuring Voltage Between VTEC Oil Pressure Switch 2-Pin Connector Terminals No. 1 & 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 VTEC oil pressure switch and G101.
15. Turn the ignition switch OFF.
16. Disconnect the VTEC solenoid valve 2P connector.
17. Check for resistance between VTEC solenoid valve 2P connector terminals No. 1 and No. 2.
    Fig 6: Checking Resistance Between VTEC Solenoid Valve 2-Pin Connector Terminals No. 1 & No. 2

    Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there 14-30 ohm? 

    1. YES  - Go to step 18.
    2. NO  - Replace the VTEC solenoid valve (see VTEC Solenoid Valve Removal/Inspection  ).
18. Remove the VTEC oil pressure switch (A) and install the special tools as shown, then reinstall the VTEC oil pressure switch.
    Fig 7: Removing/Installing VTEC Oil Pressure Switch

    Courtesy of AMERICAN HONDA MOTOR CO., INC.
19. Reconnect the VTEC solenoid valve 2P connector and VTEC oil pressure switch 2P connector.
20. Connect a tachometer or the scan tool or the HDS to the DLC.
21. Start the engine. Hold the engine at 3,000 RPM with no load (in Park or neutral) until the radiator fan comes on.
22. Check the oil pressure at engine speeds of 1,000 and 2,000 RPM. Keep the measuring 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/cm ²  , 7 psi)? 

    1. YES  - Go to step 23.
    2. NO  - Inspect the VTEC solenoid valve (see VTEC Solenoid Valve Removal/Inspection  ).
23. Turn the ignition switch OFF.
24. Disconnect the VTEC solenoid valve 2P connector.
25. Attach the battery positive terminal to VTEC solenoid valve 2P connector terminal No. 2.
26. Start the engine, then connect the battery negative terminal to 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 VTEC solenoid valve (see VTEC Solenoid Valve Removal/Inspection  ). If the valve is OK, check the engine oil pressure (see OIL PRESSURE TEST ).
27. With the battery terminals still connected to the 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 & 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 VTEC oil pressure switch (see VTEC Solenoid Valve Removal/Inspection  ).
28. Turn the ignition switch OFF.
29. Disconnect the battery terminals from the 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 & Body Ground

    Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    1. YES  - Repair short in the wire between the VTEC solenoid valve and the ECM/PCM (B15).
    2. NO  - Go to step 32.
32. Connect VTEC solenoid valve 2P connector terminal No. 2 to body ground with a jumper wire.
    Fig 10: Connecting VTEC Solenoid Valve 2-Pin 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 & 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, then recheck (see ECM/PCM UPDATING AND SUBSTITUTION FOR TESTING ). If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM.
    2. NO  - Repair open in the wire between the VTEC solenoid valve and the ECM/PCM (B15).