Diagnostic Procedure
- Turn ignition off. Connect New Generation Star (NGS) tester or equivalent to OBD-II Data Link Connector-2 (DLC-2). See Figure. Turn ignition on. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check for service bulletins and/or other line of repair information related to this DTC. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 6. If repair information is not available, go to next step.
- Turn ignition off. Disconnect fuel sending unit 4-pin harness connector. See Fig 1. Check for poor connection at terminal due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary and go to step 6.
- With fuel sending unit harness connector disconnected, inspect fuel sending unit. See FUEL GAUGE SENDING UNIT under COMPONENT TESTS in INSTRUMENT PANELS - MX-5 MIATA article in ACCESSORIES & EQUIEMENT. If fuel sending unit is okay, go to next step. If fuel sending unit is faulty, replace fuel sending unit. After repair, go to step 6.
- Turn ignition off. Leave fuel sending unit harness connector disconnected and disconnect PCM 31-pin harness connector. See Fig 1. Check continuity between ground and fuel sending unit connector terminal "C" (Brown/Black wire). If continuity is not found, go to next step. If continuity is found, repair short circuit to ground (in Brown/Black wire) between fuel sending unitand PCM. For circuit identification, see MIATA
in WIRING DIAGRAMS article. After repair go to step 6.
- With fuel sending unit and PCM harness connector disconnected, check continuity between fuel sending unit connector terminal "A" (Black wire) and C" (Brown/Black wire). If continuity is not found, go to next step. If continuity is found, repair short circuit betweenfuel sending unit wires (Brown/Black and Black wire). After repair go to next step.
- Return vehicle to original condition. Using NGS tester or equivalent, clear DTCs from PCM memory. Start engine and let it idle until it reaches normal operation temperature. Monitor for DTCs. If same DTC P0462 is present, replace PCM. For PCM removal and installation, see POWERTRAIN CONTROL MODULE
in REMOVAL, OVERHAUL & INSTALLATION article. If any other DTC is present, follow appropriate DTC diagnostic procedure.
Courtesy of MAZDA MOTORS CORP.