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Home >> Mitsubishi >> 2002 >> Montero Sport ES, RWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0121: Throttle Position (TP) Sensor Circuit Range/Performance Problem >> Test Procedure

Test Procedure

  1. Turn ignition on. Using scan tool, check data list item No. 14 (throttle position sensor). Turn ignition on. With throttle valve in idle position, voltage should be 0.535-0.735 volt. With throttle valve in fully open position, voltage should be 4.5-5.5 volts. If voltages are as specified, problem is intermittent. See INTERMITTENT DIAGNOSTIC TROUBLE CODES . If voltages are not as specified, go to next step.
  2. Turn ignition off. Disconnect TP sensor 4-pin connector. See Figure. Check TP sensor connector for loose, damaged or corroded terminals. If problem exists, repair or replace connector. Go to step  14. If problem does not exist, go to next step.
  3. Measure resistance between TP sensor terminals No. 1 and 4 (component side). Resistance should be 3.5-6.5 K ohms. Also, measure resistance between TP sensor terminals No. 1 and 3 (component side) while moving throttle valve from idle position to full throttle position. Resistance should change smoothly in proportion to the opening angle of throttle valve. If both resistance checks are as specified, go to next step. If either resistance checks are not as specified, replace TP sensor . Go to step  14.
  4. Turn ignition on. Measure voltage between ground and TP sensor connector terminal No. 4 (Green/Yellow wire). Voltage should be 4.8-5.2 volts. If voltage is as specified, go to step  7. If voltage is not as specified, go to next step.
  5. Turn ignition off. Disconnect PCM connector C-90. See Figure. Check PCM connector C-90 for loose, damaged or corroded terminals. If problem exists, repair or replace connector. Go to step  14. If problem does not exist, go to next step.
  6. Check continuity between TP sensor connector terminal No. 4 and PCM connector C-90 terminal No. 46. See Figure and Figure . Continuity should exist. Then, check continuity between ground and TP sensor connector terminal No. 4. Continuity should not exist. If continuity is not as specified, repair open or short to ground in Green/Yellow wire between TP sensor and PCM. Go to step  14. If continuity is as specified, replace PCM. Go to step  14.
  7. Turn ignition off. Check for continuity between ground and TP sensor connector terminal No. 1 (Black wire). If continuity exists, go to step  10. If continuity does not exist, go to next step.
  8. Disconnect PCM connector C-90. Check PCM connector C-90 for loose, damaged or corroded terminals. See Figure. If problem exists, repair or replace connector. Go to step  14. If problem does not exist, go to next step.
  9. Check for open or damage in Black wire between TP sensor connector terminal No. 1 and PCM connector C-90 terminal No. 57. See Figure and Figure . If problem exists, check 33-pin intermediate connector C-71 for damage and repair as necessary. If 33-pin intermediate connector C-71 is OK, repair Black wire. Go to step  14. If problem does not exist, check 33-pin intermediate connector C-71 for damage and repair as necessary. If 33-pin intermediate connector C-71 is OK, replace PCM. Go to step  14.
  10. Check PCM connectors C-90 and C-91 for loose, damaged or corroded terminals. See Figure. If problem exists, repair or replace connector(s). Go to step  14. If problem does not exist, go to next step.
  11. Check continuity between TP sensor connector terminal No. 3 (Green/White wire) and PCM connector C-91 terminal No. 78. See Figure. Continuity should exist. Then check continuity between ground and TP sensor connector terminal No. 3 (Green/White wire). Continuity should not exist. If continuity is not as specified, repair open or short to ground in Green/White wire. Go to step  14. If continuity is as specified, go to next step.
  12. Check TP sensor adjustment. See TP SENSOR ADJUSTMENT for ECLIPSE, ECLIPSE SPYDER, GALANT, MONTERO & MONTERO SPORT under THROTTLE POSITION (TP) SENSOR & ACCELERATOR PEDAL POSITION SENSOR in ON-VEHICLE ADJUSTMENTS article. If TP sensor is out of adjustment, adjust TP sensor. Go to step  14. If TP sensor is not out of adjustment, go to next step.
  13. Turn ignition on. Using scan tool, check data list item No. 14 (throttle position sensor). With throttle valve in idle position, voltage should be 0.535-0.735 volt. With throttle valve in fully open position, voltage should be 4.5-5.5 volts. If voltages are as specified, problem is intermittent. See INTERMITTENT DIAGNOSTIC TROUBLE CODES . If voltages are not as specified, replace PCM. Go to next step.
  14. Test drive vehicle following OBD-II drive cycle other monitor pattern. See OTHER MONITOR  under OBD-II DRIVE CYCLES under VERIFYING REPAIRS. Check for DTCs. If DTC P0121 is output, go to step  1and retry test procedure. If DTC P0121 is not output, inspection is complete.
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