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 7. If repair information is not available, go to next step.
- Turn ignition off. Disconnect EGR boost sensor 3-pin harness connector. See Fig 1. Turn ignition on. Measure voltage between ground and EGR boost sensor harness connector terminal "B" (Blue/Yellow wire). For circuit identification, see MIATA
in WIRING DIAGRAMS article. Voltage should be above 4.8 volts. If voltage is as specified, go to next step. If voltage is not as specified, go to step 5.
- Before proceeding with step 4), check retrieved DTCs. If DTCs P0122 and P0452 are also present with P0107, see REFERENCE VOLTAGE TEST trouble shooting procedure. If no other DTCs is present, go to next step.
- Leave ignition on and EGR boost sensor harness connector disconnected. Measure voltage between ground and EGR boost sensor harness connector terminal "C" (Light Green/Red wire). Voltage should be 4.5-5.5 volts. If voltage is as specified, check for poor connection at EGR boost sensor harness connector terminal "C" (Light Green/Red wire). If connector is faulty, repair or replace a necessary and go to step 7. If connector is okay, replace EGR boost sensor and go to step 7. If voltage is not as specified, repair open or short circuit (in Light Green/Red wire) between PCM and EGR boost sensor. After repair, go to step 7.
- Turn ignition off. Leave EGR boost sensor harness connector disconnected and disconnect PCM 31-pin harness connector. See Fig 1. Check continuity between ground and EGR boost sensor harness connector terminal "B" (Blue/Yellow wire). If continuity is not found, go to next step. If continuity is found, repair short circuit to ground (in Blue/Yellow wire) between EGR boost sensor and PCM. After repair, go to step 7.
- With EGR boost sensor and PCM harness connector disconnected, check continuity between EGR boost sensor harness connector terminals "B" (Blue/Yellow wire) and "A" (Black/Red wire). If continuity is not found, go to next step. If continuity is found, repair short between EGR boost sensor harness circuits (Blue/Yellow and Black/Red wires). 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 P0107 is present, replace PCM. For PCM removal and installation, see POWERTRAIN CONTROL MODULE
under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. If any other DTC is present, follow appropriate DTC diagnostic procedure.
Courtesy of MAZDA MOTORS CORP.