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Home >> Mitsubishi >> 2002 >> Lancer ES, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0122: Throttle Position Sensor Circuit Low Input >> Diagnostic Procedure
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Diagnostic Procedure

CAUTION: To prevent damage to scan tool, always turn ignition switch to LOCK position before connecting or disconnecting scan tool.
  1. Using scan tool, check throttle position sensor. Connect scan tool to data link connector. Turn ignition on. Set scan tool to the data reading mode for data list item 14: THROTTLE POSITION SENSOR. With throttle valve in idle position, voltage should be 0.335-0.935 volt. With throttle valve in full-open position, voltage should be 4.4-5.3 volts. Turn ignition switch to LOCK position. If sensor is not operating properly, go to next step. If sensor is operating properly, malfunction is intermittent.
  2. Check throttle position sensor harness connector for damage. If connector is in good condition, go to next step. If connector is not in good condition, repair or replace as necessary. After repairs, go to step  11 .
  3. Check supply voltage at throttle position sensor. Disconnect throttle position sensor harness connector. Turn ignition on. Using a DVOM, measure voltage between throttle position sensor harness connector terminal No. 3 and ground. Voltage should be 4.8-5.2 volts. Turn ignition switch to LOCK position. If voltage is not as specified, go to next step. If voltage is as specified, go to step  6 .
  4. Check ECM harness connector C-115 (M/T) or PCM harness connector C-118 (A/T) for damage. If connector is in good condition, go to next step. If connector is not in good condition, repair or replace as necessary. After repairs, go to step  11 .
  5. Check for open or short circuit to ground between throttle position sensor harness connector terminal No. 3 and ECM harness connector C-115 terminal No. 81 or PCM harness connector C-118 terminal No. 46 (A/T). If wiring harness is in good condition, replace ECM or PCM. After replacing ECM or PCM, go to step  11 . If wiring harness is not in good condition, repair wiring harness. After repairs, go to step  11 .
  6. Check throttle position sensor. Disconnect throttle position harness connector. Using DVOM, measure resistance between throttle position sensor terminals No. 2 and 3. Resistance should be 2-4 k/ohms. Measure resistance between throttle position sensor terminals No. 1 and 2. Move throttle valve from idle position to full-open position. Resistance should change smoothly in proportion to the opening angle of throttle valve. If resistance is as specified, go to next step. If resistance is not as specified, replace throttle position sensor. After replacing sensor, go to step  11 .
  7. Check ECM harness connector C-115 (M/T) or PCM harness connectors C-116 and C-118 at (A/T) for damage. If connector(s) are in good condition, go to next step. If connector(s) are not in good condition, repair or replace as necessary. After repairs, go to step  11 .
  8. Check for open circuit and short circuit to ground between throttle position sensor harness connector terminal No. 1 and ECM harness connector C-115 terminal No. 84 or PCM harness connector C-116 terminal No. 78 (A/T). If wiring harness is in good condition, go to next step. If wiring harness is not in good condition, repair as necessary. After repairs, go to step  11 .
  9. Check for short circuit to ground between throttle position sensor harness connector and auto-cruise control ECU. If wiring harness is in good condition, go to next step. If wiring harness is not in good condition, repair as necessary. After repairs, go to step  11 .
  10. Using scan tool, check throttle position sensor. Connect scan tool to data link connector. Turn ignition on. Set scan tool to data reading mode for data list item 14: THROTTLE POSITION SENSOR. With throttle valve in idle position, voltage should be 0.335-0.935 volt. With throttle valve in full-open position, voltage should be 4.4-5.3 volts. Turn ignition switch to LOCK position. If sensor is operating properly, malfunction is intermittent. If sensor is not operating properly, replace ECM or PCM. After replacing ECM or PCM, go to next step.
  11. Test the OBD-II drive cycle. Carry out a test drive with the drive cycle pattern. See OTHER MONITOR  under VERIFYING REPAIRS. Check for DTCs. If DTC P0122 is output, repeat diagnosis. If DTC P0122 is not output, inspection is complete.
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