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Home >> Mazda >> 2001 >> MX-5 Miata Base, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0122: Throttle Position (TP) Sensor Circuit, Low Input >> Diagnosis & Repair Procedure
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Diagnosis & Repair Procedure

  1. Ensure FREEZE FRAME DATA has been recorded. Check for related service bulletins. Repair as necessary and go to next step.
  2. Turn ignition on. Using scan tool, access TP V PID data. Slowly depress accelerator pedal. If TP V PID is less than 0.1 volt, go to next step. If TP V PID is 0.1 volt or more, problem is intermittent. See TROUBLE SHOOTING - NO CODES article.
  3. Turn ignition off. Disconnect TP sensor connector. Connect a jumper wire between TP sensor harness connector terminals "A" (Light Green/Red wire) and "C" (Green/Black wire). See Fig 1. Turn ignition on. Using scan tool, access TP V PID data. If TP V PID is more than 4.8 volts, go to next step. If TP V PID is 4.8 volts or less, go to step  5.
  4. Turn ignition off. Check for continuity between TP sensor terminals "A" and "C". See Fig 1. If continuity is present, check TP sensor connector for loose or damaged terminals, poor contact or corrosion. Repair as necessary and go to step  8. If continuity is not present, replace TP sensor and go to step  8.
    5. NOTE: If DTC P0107 and P0452 are present, check reference voltage. See REFERENCE VOLTAGE TEST .
  5. Turn ignition on. Measure voltage between ground and TP sensor harness connector terminal "A" (Light Green/Red wire). See Fig 1. If 4.5-5.5 volts are present, go to next step. If 4.5-5.5 volts are not present, repair open circuit in Light Green/Red wire between TP sensor and PCM connector terminal No. 4L. See WIRING DIAGRAMS article. Go to step  8.
  6. Turn ignition off. Disconnect appropriate PCM connectors. Check for continuity of Green/Black wire between TP sensor harness connector terminal "C" and PCM harness connector terminal No. 4V. See Figure and Fig 1 . If continuity is present, go to next step. If continuity is not present, repair open in Green/Black wire. See WIRING DIAGRAMS article. Go to step  8.
  7. Check for continuity between ground and PCM harness connector terminal No. 4V (Green/Black wire). See Figure. If continuity is not present, repair short between Black/Red wire and Green/Black wire, and go to next step. If continuity is present, repair short to ground in Green/Black wire and go to next step. See WIRING DIAGRAMS article.
  8. Reconnect all connectors. Clear DTCs. See CLEARING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. Start engine and allow it to reach normal operating temperature. Check for DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. If DTC P0122 is present, replace PCM and go to next step. On vehicles equipped with immobilizer system, reprogram ignition key identification numbers. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION. If DTC P0122 is not present, go to next step.
  9. Cycle ignition from off to on. Check for DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. If any other DTC is present, go to appropriate test.
Fig 1: Identifying Throttle Position (TP) Sensor Connector Terminals
G00032518Courtesy of MAZDA MOTORS CORP.
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