Download DTC Service Manual : P1259 ’01 Honda Accord – DTC P1259: A problem in the VTEC Oil Pressure Switch circuit or VTEC Solenoid Valve circuit Special Tools Required Pressure Gauge Adaptor 07NAJ-P07010A A/T Low Pressure Gauge W/Panel 07406-0070300 A/T Pressure Hose, 2,210 mm 07MAJ-PY4011A A/T Pressure Adaptor 07MAJ-PY40120 1. Do the 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  position 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 1st road test, repeat this test two more times. Is DTC P1259 indicated? YES – Go to step 5. NO – 5. Turn the ignition switch OFF. 6. Disconnect the VTEC oil pressure switch connector. 7. Check for continuity on the VTEC oil pressure switch between the 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 the VTEC oil pressure switch harness connector No. 1 terminal and body ground.