1998 Isuzu Oasis LSFACTORY OEM SERVICE PROCEDURE

Power Steering Pressure Switch Signal

NOTE: This signal informs PCM when power steering load is high.
  1. Turn ignition on. Measure voltage between PCM connector terminals A26 and B20 (Accord, CR-V, Oasis & Odyssey) or terminals A9 and C16 (Civic & Prelude). See Figure . If voltage is one volt or more, go to step 3). If voltage is less than one volt, go to next step.
  2. Start engine. Turn steering wheel slowly to full lock position. Measure voltage between PCM connector terminals A26 and B20 (Accord, CR-V, Oasis & Odyssey) or terminals A9 and C16 (Civic & Prelude). If battery voltage is present, Power Steering Pressure (PSP) switch signal is okay. If battery voltage is not present, go to step 4).
  3. Turn ignition off. Disconnect PSP switch 2-pin connector. Switch is located on high pressure hose next to steering gear. Connect a fused jumper wire between the two PSP switch harness connector terminals. Turn ignition on. Measure voltage between PCM connector terminals A26 and B20 (Accord, CR-V, Oasis & Odyssey) or terminals A9 and C16 (Civic & Prelude). If voltage is one volt or more, repair open in wire between PCM connector terminal B20 (Accord, CR-V, Oasis & Odyssey) or C16 (Civic & Prelude) and PSP switch. If wire is okay, repair Black wire between PSP switch and ground connection. See WIRING DIAGRAMS article. If voltage is less than one volt, replace PSP switch.
  4. Turn ignition off. Disconnect PSP switch 2-pin connector. Switch is located on high pressure hose next to steering gear. Turn ignition on. Measure voltage between PCM connector terminals A26 and B20 (Accord, CR-V, Oasis & Odyssey) or terminals A9 and C16 (Civic & Prelude). If battery voltage is present, replace PSP switch. If battery voltage is not present, go to next step.
  5. Turn ignition off. Disconnect PCM 32-pin connector A (Accord, CR-V, Oasis & Odyssey) or 31-pin connector "C" (Civic & Prelude). See Figure . Check for continuity between ground and PCM connector terminal A26 (Accord, CR-V, Oasis & Odyssey) or C16 (Civic & Prelude). If continuity exists, repair short in wire between PCM connector terminal A26 (Accord, CR-V, Oasis & Odyssey) or C16 (Civic & Prelude) and PSP switch connector. See WIRING DIAGRAMS article. If continuity does not exist, substitute a known good PCM, then recheck for voltage. If battery voltage now exists, replace original PCM.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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