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Home >> Mazda >> 2003 >> MX-5 Miata Base, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P1634: Generator Terminal "B" Circuit Open >> Diagnostic Procedure
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Diagnostic Procedure

  1. Verify Related Repair Information Availability -  Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step  6.
  2. Inspect Battery -  Turn ignition off. Perform battery inspection. If battery is okay, go to next step. If battery is faulty, replace battery. After repair, go to step  6.
  3. Inspect Generator Terminal For Poor Installation -  Check generator harness connector terminal "B" (White wire) for loose nut. See Figure. If generator terminal installation nut is tight, go to next step. If generator terminal installation nut is loose, retighten installation nut. After repair, go to step  6.
  4. Inspect Poor Installation Of Battery Positive Terminal -  Check for looseness of positive battery terminal. If positive battery terminal is tight, go to next step. If positive battery terminal is loose, reinstall battery terminal correctly on post and tighten clamping bolt. After repair, go to step  6.
  5. Inspect Battery Charging Circuit -  Start engine and let it idle. Disconnect positive battery terminal while engine is running. If engine does not stall, go to next step. If engine stalls, repair or replace open circuit in White wire between generator harness connector terminal and positive battery terminal. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to next step.
  6. Verify Troubleshooting Of DTC P1634 Completed -  Return vehicle to original condition. Connect scan tool to DLC-2. See Figure. Clear DTCs from PCM memory. See CLEARING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P1634 is present, replace PCM. For PCM removal and installation, see POWERTRAIN CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
  7. 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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