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Home › Mazda › 2002 › MPV ES › Repair and Diagnosis › Engine Performance › System › Engine Controls - Self-Diagnostics › Diagnostic Tests › DTC P0550: Power Steering Switch Malfunction › Diagnostic Procedures

Diagnostic Procedures

  1. Record freeze frame data. Check for service bulletins and on-line information. Repair as necessary. After repair, go to next step.
  2. Inspect PSP Switch -  Check PSP switch. See POWER STEERING PRESSURE SWITCH under SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If PSP switch is okay, go to next step. If PSP switch is faulty, replace PSP switch. After repair, go to step  4.
  3. Inspect PSP Switch Signal Circuit For Short To Ground -  Turn ignition off. Disconnect PCM 104-pin harness connector. Check for continuity between ground and PSP switch harness connector terminal (Black/Blue wire). See appropriate wiring diagram under ENGINE PERFORMANCE in WIRING DIAGRAMS. If continuity is not present, go to next step. If continuity is present, repair short to ground in Black/Blue wire between PSP switch harness connector terminal and PCM 104-pin harness connector terminal No. 31. See Figure. After repair, go to next step.
  4. Verify Trouble Shooting Of DTC P0550 Completed -  Reconnect all disconnected connectors. Start engine. Using scan tool, clear DTC. See CLEARING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. Drive vehicle at more than 37 MPH for one minute. Ensure ECT PID is more than 140°F (60°C). Recheck DTCs. If DTC P0550 is present, replace PCM. After repair, go to next step. If DTC P0550 is not present, go to next step.
  5. Verify After Repair Procedure -  Using scan tool, perform After Repair Procedure. See AFTER REPAIR PROCEDURE . If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.
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