P1259

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, 2,210 mm 07MAJ-PY4011A
- A/T pressure adapter 07MAJ-PY40120

1. Check the engine oil level, and refill it if necessary.
2. Reset the ECM/PCM control module. Testing and Inspection See clearing trouble codes.
3. Start the engine. Hold the engine and warm 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 that engine speed for at least 2 seconds. If DTC P1259 is not repeated during the first road test, repeat this test 2 more times.
Is DTC P1259 indicated?
YES - Go to step 5
NO - Intermittent failure, the system is OK at this time. Check for poor connections or loose wires at the VTEC solenoid valve and at the PCM.
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 VTEC oil pressure switch - 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 VTEC oil pressure switch 2P connector terminal No. 1 and body ground.
Is there battery voltage?
YES - Go to step 11.
NO - Go to step 10.











10. Inspect for an open or short to ground in the wire between the VTEC oil pressure switch and the ECM (A20)/PCM (C10). If the wire is OK, substitute a known-good ECM/PCM and recheck.






11. Measure voltage across the VTEC oil pressure switch harness 2P connector.
Is there battery voltage?
YES - Go to step 12.
NO - Repair open in the wire between the VTEC oil pressure switch and C101, G102. if the wire is OK, substitute a known-good ECM/PCM and recheck.
12. Turn the ignition switch OFF.
13. Disconnect VTEC solenoid valve (1P) connector.






14. Check for continuity between VTEC solenoid valve (1P) connector terminal and body ground.
Is there 14 - 30 Ohms resistance?
YES - Go to step 15.
NO - Replace the VTEC solenoid valve.






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 2P connector and VTEC oil pressure switch 2P connector.
17. Connect a tachometer.
18. Warm the engine with no load (in Park or neutral) until the radiator fan comes on.
19. 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 1 minute).
Is pressure below 49 kPa (0.5 kgf/sq.cm 7 psi)?
YES - Go to step 20.
NO - Inspect the VTEC solenoid valve. Testing and Inspection See VTEC solenoid valve test.
20. Turn the ignition switch OFF.
21. Disconnect the VTEC solenoid valve 1P connector.
22. Attach the battery positive terminal 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 390 kPa (4.0 kgf/Sq.cm, 57 psi)?
YES - Go to step 24.
NO - Inspect the VTEC solenoid valve. Testing and Inspection See VTEC solenoid valve test.






A/T






M/T

24. With the battery positive terminal still connected to the VTEC solenoid valve, measure voltage between PCM connector C10 (A/T) or ECM connector terminal A20 (M/T) 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 terminal from the VTEC solenoid valve terminal.






A/T






M/T

27. Check for continuity between the VTEC solenoid valve harness 1P connector terminal and PCM connector terminal B12 (A/T) or ECM connector terminal B2 (M/T).
Is there continuity?
YES - Go to step 28.
NO - Repair open in the wire between the PCM connector terminal B12 (A/T) or ECM connector terminal B2 (M/T) and VTEC solenoid valve connector.






28. Check for continuity between the VTEC solenoid valve 1P connector and body ground.
Is there continuity?
YES - Repair short in the wire between the PCM connector terminal B12 (A/T) or ECM connector terminal B2 VTEC solenoid valve connector.
NO - Substitute a known-good ECM/PCM and recheck. If symptom/indication goes away, replace the original ECM/PCM.