P1259

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

Special Tools Required
^ Pressure gauge adapter 07NAJ-P07010A
^ A/T low pressure gauge w/panel 07406-0070300
^ A/T pressure hose, 2,210 mm 07MAJ-PY4011A
^ A/T pressure hose adapter 07MAJ-PY40120

NOTE: Check the engine oil level, and refill it if necessary.

1. Do the engine control module (ECM) 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 1st gear to an engine speed over 4,000 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?
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.
5. Turn the ignition switch OFF.
6. Disconnect the VTEC oil pressure switch 2P connector.





7. Check for continuity on the VTEC oil 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 oil pressure switch.
8. Turn the ignition switch ON (II).





9. Measure the voltage between the VTEC oil pressure switch harness 2P connector terminal No.1 and body ground.
Is there about 12 V?
YES- Go to step 10.
NO- Inspect for an open or a short to ground in the wire between the VTEC pressure switch and the ECM (C10). If the wire is OK, substitute a known-good ECM and recheck.





10. Measure voltage across the VTEC oil pressure switch harness 2P connector.
Is there battery voltage?
YES- Go to step 11.
NO- Repair an open in the wire between the VTEC oil pressure switch and G101. If the wire is OK, substitute a known-good ECM 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 engine cover and engine cover bracket.





15. Remove the VTEC oil pressure switch (A) and install the special tools as shown, then reinstall the VTEC oil pressure switch.
16. Reconnect the VTEC solenoid valve 1P connector and VTEC oil pressure switch 2P connector.
17. Connect a Honda PGM Tester or a tachometer.
18. Warm up the engine to normal operating temperature (cooling fan comes on).
19. Check oil pressure at engine speeds of 1,000, 2,000, and 4,000 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 20.
NO- Inspect the VTEC solenoid valve.
20. Turn the ignition switch OFF.
21. Disconnect the VTEC solenoid valve 1P connector.
22. Attach the battery positive cable to the VTEC solenoid valve terminal.
23. Start the engine and check oil pressure at an engine speed of 3,000 rpm.
Is pressure above 200 kPa (2.0 kgf/cm2, 28 psi)?
YES- Go to step 24.
NO- Inspect the VTEC solenoid valve.





24. With the battery positive cable still connected to the VTEC solenoid valve, measure voltage between ECM connector terminal C10 and body ground.
Is there battery voltage above 4,000 rpm?
YES- Go to step 25.
NO- Replace the VTEC oil pressure switch.
25. Turn the ignition switch OFF.
26. Disconnect the battery positive cable from the VTEC solenoid valve terminal.
27. Disconnect the ECM connector B (25P).





28. Check for continuity between the VTEC solenoid valve harness 1P connector terminal and ECM connector terminal B12.
Is there continuity?
YES- Go to step 29.
NO- Repair an open in the wire between ECM connector seminal B12 and VTEC solenoid valve connector.





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