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Home >> Acura >> 1997 >> Integra GS-R, 2D Coupe >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - GS-R >> Circuit Tests >> DTC P1259: VTEC Pressure Switch Or Solenoid Valve Circuits
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DTC P1259: VTEC Pressure Switch Or Solenoid Valve Circuits

  1. Perform PCM reset procedure. See PCM RESET PROCEDURE/CLEARING CODES . Start engine and run at 3000 RPM with no loads and transmission in Park or Neutral, until radiator fan comes on. Allow engine to idle. Road test vehicle. Accelerate in 1st gear to an engine speed over 6000 RPM. Hold that engine RPM for at least 2 seconds. If DTC P1259 does not reset during first road test, repeat road test 2 more times.
  2. If DTC P1259 resets, go to next step. If DTC P1259 does not reset, problem is intermittent, system is functioning properly at this time. Check for poor connections or loose wires at VTEC pressure switch, solenoid valve and PCM connectors. See the WIRING DIAGRAMS article. Repair as necessary.
  3. Turn ignition off. Disconnect VTEC pressure switch connector. Check for continuity between VTEC pressure switch terminals. If continuity exists, go to next step. If continuity does not exist, replace VTEC pressure switch.
  4. Turn ignition on. Measure voltage between ground and VTEC pressure switch harness connector terminal No. 1 (Blue/Black wire). If about 12 volts exists, go to next step. If about 12 volts does not exist, inspect for open or short to ground in Blue/Black wire between VTEC pressure switch and PCM. See the WIRING DIAGRAMS article. If wire is okay, substitute a known-good PCM and recheck. If symptom or DTC is gone, replace original PCM.
  5. Measure voltage across VTEC pressure switch harness connector terminals. If about 12 volts exists, turn ignition off and go to next step. If about 12 volts does not exist, repair open in Black wire between VTEC pressure switch and ground. See the WIRING DIAGRAMS article.
    CAUTION: When checking VTEC oil pressure, keep measuring time as short as possible (less than one minute) because engine in running with no load.
  6. Remove 10 mm oil pressure inspection bolt. Install Pressure Gauge Adaptor (Snap-On MT26-17) and oil pressure gauge. Connect tachometer. Start engine and warm to operating temperature. Check oil pressure at engine speeds of 1000, 3000 and 5000 RPM. If oil pressure is less than 7 psi, go to next step. If oil pressure is not less than 7 psi, inspect VTEC solenoid valve filter and valve plunger for clogging and smooth operation. Repair or replace as necessary.
  7. Turn ignition off and disconnect VTEC solenoid valve 2-pin connector. Using jumper wire, attach battery voltage to Green/White wire terminal on VTEC solenoid. Start engine and check oil pressure at 5000 RPM. If oil pressure is more than 60 psi, go to next step. If oil pressure is not more than 60 psi, inspect VTEC solenoid valve filter and valve plunger for clogging and smooth operation. Repair or replace as necessary.
  8. Turn ignition off. Reconnect VTEC pressure switch. Start engine. With battery voltage connected to VTEC solenoid valve, measure voltage between PCM 31-pin connector terminal No. 15 (Blue/Black wire) and PCM 32-pin connector terminal No. 10 (Black wire) or No. 23 (Black wire). See Figure. If about 12 volts exists at an engine speed greater than 5000 RPM, go to next step. If about 12 volts does not exist at an engine speed greater than 5000 RPM, replace VTEC pressure switch.
  9. Turn ignition off. Disconnect battery voltage from VTEC solenoid valve. Check for continuity between ground and VTEC solenoid valve terminal. If resistance is 14-30 ohms, go to next step. If resistance is not 14-30 ohms, replace VTEC solenoid valve.
  10. Check for continuity between VTEC solenoid harness connector terminal (harness side) and PCM 32-pin connector terminal No. 8 (Green/Yellow wire). See Figure. If continuity exists, go to next step. If continuity does not exist, repair open in Green/Yellow wire between VTEC solenoid harness connector terminal and PCM connector. See the WIRING DIAGRAMS article.
  11. Check for continuity between ground and VTEC solenoid harness connector terminal. If continuity does not exist, substitute a known-good PCM and recheck. If symptom or DTC is gone, replace original PCM. If continuity exists, repair short to ground in Green/Yellow wire between VTEC solenoid harness connector terminal and PCM connector. See the WIRING DIAGRAMS article.
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