P1259

DTC P1259: A problem in the VTEC Oil Pressure Switch circuit or VTEC Solenoid Valve circuit.

Special Tools Required
- Pressure Gauge Adaptor O7NAJ-P07010A
- A/T Low Pressure Gauge W/Panel 07406-0070300
- A/T Pressure Hose 07406-0020201
- A/T Pressure Hose, 2,210 mm O7MAJ-PY4011A
- A/T Pressure Adaptor O7MAJ-PY4O120

1. Do the engine control module (ECM)/powertrain control module (PCM) reset procedure.

2. Start the engine.
3. Warm up the engine to normal operating temperature (cooling fan comes on).
4. Road test the vehicle:
Accelerate in 2 Position (second gear) to an engine speed over 4,000 rpm. Hold that engine speed for at least two seconds. If DTC P1259 is not repeated during the first road test, repeat this test two more times.
Is DTC P1259 indicated?
YES - Go to step 5.
NO - Intermittent failure, system is OK at this time. Check for poor connections or loose wires at VTEC solenoid valve and ECM/PCM.
5. Turn the ignition switch OFF.
6. Disconnect the VTEC pressure switch 2P connector.




7. Check for continuity on the VTEC pressure switch between the pressure switch 2P connector terminals No.1 and No.2.
Is there continuity?
YES - Go to step 8.
NO - Replace the VTEC pressure switch.
8. Turn the ignition switch ON (II).
9. Measure the voltage between the VTEC pressure switch harness 2P connector terminal No.1 and body ground.
Is there approx. 12 V?
YES - Go to step 10.
NO - Inspect for an open or short to ground in the wire between the VTEC pressure switch and the ECM/PCM (C1O). If the wire is OK, substitute a known-good ECM/PCM and recheck.




10. Measure voltage across the VTEC pressure switch harness 2P connector.
Is there battery voltage?
YES - Go to step 11.
NO - Repair open in the wire between the VTEC pressure switch and G101. If the wire is OK, substitute a known-good PCM and recheck.
11. Turn the ignition switch OFF.
12. Disconnect the VTEC solenoid valve 1P connector.




13. Check for continuity on the VTEC solenoid valve between the solenoid valve 1P connector terminal and body ground.
Is there 14 - 30 Ohms?
YES - Go to step 14.
NO - Replace the VTEC solenoid valve.




14. Remove the VTEC pressure switch (A) and install the special tools as shown, then reinstall the VTEC pressure switch.
15. Reconnect the VTEC solenoid valve 1P connector and VTEC pressure switch 2P connector.
16. Connect a tachometer.
17. Warm up the engine to normal operating temperature (cooling fan comes on).
18. Check oil pressure at engine speeds of 1,000, 2,000 and 3,000 rpm. Keep measuring time as short as possible because the engine is running with no load (less than one minute).
Is pressure below 49 kPa (0.5 kgf/cm2, 7 psi)?
YES - Go to step 19.
NO - Inspect the VTEC solenoid valve.
19. Turn the ignition switch OFF.
20. Disconnect the VTEC solenoid valve 1P connector.
21. Attach the battery positive terminal to the VTEC solenoid valve terminal.
22. Start the engine and check oil pressure at an engine speed of 3,000 rpm.
Is pressure above 390 kPa (4.0 kgf/cm2, 57 psi)?
YES - Go to step 23.
NO - Inspect the VTEC solenoid valve.




23. With the battery positive terminal still connected to the VTEC solenoid valve, measure voltage between C1O and body ground.
Is there battery voltage above 4,000 rpm?
YES - Go to step 24.
NO - Replace the VTEC pressure switch.

24. Turn the ignition switch OFF.
25. Disconnect the battery positive terminal from the VTEC solenoid valve terminal.




26. Check for continuity between the VTEC solenoid valve harness 1P connector terminal and the ECM/PCM connector terminal B12.
Is there continuity?
YES - Go to step 27.
NO - Repair open in the wire between the ECM/PCM (B12) and VTEC solenoid valve connector.




27. Check for continuity between the VTEC solenoid valve 1 P connector terminal and body ground.
Is there continuity?
YES - Repair short in the wire between the ECM/PCM (B12) and VTEC solenoid valve connector.
NO - Substitute a known-good ECM/PCM and recheck. If symptom/indication goes away, replace the original ECM/PCM.