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Home >> Mazda >> 2002 >> Tribute LX, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 5 (Engine Controls - Tests W/Codes - 2.3L) >> Circuit Tests >> DTC P0120 - Throttle Position (TP) Sensor Circuit Malfunction >> Diagnosis & Repair Procedure

Diagnosis & Repair Procedure

WARNING: This page is about a different car, the 1997 Mazda Millenia. However, it is still accessible from the selected car via links, so may be relevant.
  1. Inspect all applicable harness connectors. Repair as needed. Turn ignition on. Access ECM harness connector. ECM is mounted in front of center console, under radio. Using voltmeter, backprobe applicable ECM harness connector. Measure voltage between ground and terminal No. 3B.
  2. Turn ignition on. Slowly depress accelerator pedal to wide open throttle. Voltage should increase evenly as throttle opening is increased. If TP sensor voltage changes as specified, go to step 6). If TP sensor voltage does not change as specified, go to next step.
  3. Turn ignition off. Disconnect TP sensor connector. Turn ignition on. Measure voltage between ground and terminal "A" on TP sensor harness connector. If 5 volts is present, go to next step. If 5 volts is not present, check for open or short circuit between TP sensor and ECM. Repair as needed.
  4. Check continuity of Black/Yellow wire between terminal "D" on TP sensor harness connector and terminal No. 3AB on ECM harness connector. Repair as needed. If continuity exists, go to next step.
  5. Check continuity of Yellow wire between terminal "B" on TP sensor harness connector and terminal No. 3B on ECM harness connector. Repair as needed. If continuity exists, go to next step.
  6. Inspect MAF sensor. See appropriate SYSTEM/COMPONENT TESTS - 2.3L article. Replace as needed. If MAP sensor is okay, go to next step.
  7. Erase DTCs. See CLEARING CODES  in SELF-DIAGNOSTIC SYSTEM section. If DTC resets, replace ECM. If DTC is not present, intermittent poor harness connection may have caused DTC to originally set.
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