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Home >> Mitsubishi >> 2002 >> Lancer ES, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0181: Fuel Temperature Sensor Circuit Range/Performance Problem >> 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 fuel temperature sensor. Connect scan tool to data link connector. Turn ignition on. Set scan tool to the data reading mode for data list item 4A: FUEL TEMPERATURE SENSOR. Data should be approximately the same as the outside temperature when engine is cooled. 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 fuel temperature 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  12 .
  3. Disconnect fuel temperature sensor harness connector. Using a DVOM, measure resistance between fuel temperature sensor terminals No. 1 and 3. Standard value is 0.5-12.0 k/ohms. If resistance is as specified, go to next step. If resistance is not as specified, replace fuel temperature sensor. After replacing sensor, go to step  12 .
  4. Check for continuity between fuel temperature sensor harness connector terminal No. 1 and ground. Resistance should be less than 2 ohms. If continuity is as specified, go to next step. If continuity is not as specified, repair open circuit or harness damage wiring harness between fuel temperature sensor connector terminal No. 1 and ground. After repairs, go to step  12 .
  5. Turn ignition on. Measure voltage between fuel temperature sensor harness connector terminal No. 3 and ground. Voltage should be 4.5-4.9 volts. Turn ignition switch to LOCK position. If voltage is as specified, go to next step. If voltage is not as specified, go to step  10 .
  6. Check sensor supply voltage at ECM harness connector C-115 (M/T) or PCM harness connector C-118 (A/T) by backprobing. Do not disconnect ECM or PCM harness connector. Turn ignition on. Measure voltage between terminal ECM harness connector C-115 No. 77 (M/T) or PCM harness connector terminal No. 51 (A/T) and ground by backprobing. See FUEL TEMPERATURE SENSOR OUTPUT VOLTAGE  table. Turn ignition switch to LOCK position. If voltage is as specified, go to next step. If voltage is not as specified, go to step  8 .
    FUEL TEMPERATURE SENSOR OUTPUT VOLTAGE

    Fuel Temperature - °F (°C) Voltage
    32 (0) 2.7-3.1
    68 (20) 2.1-2.5
    104 (40) 1.6-2.0
    176 (80) 0.8-1.2
  7. Check ECM harness connector C-115 at ECM (M/T) or PCM harness connector C-118 at PCM (A/T) for damage. If connector is in good condition, check intermediate connectors C-122, C-127 and D-14 for damage. Repair or replace as necessary. After repairs, go to step  12 . If intermediate connectors are in good condition, repair open in wiring harness between fuel gauge unit connector D-14 terminal No. 3 and ECM harness connector C-115 terminal No. 77 (M/T) or PCM harness connector C-118 terminal No. 51 (A/T). After repairs, go to step  12 .
  8. Check ECM harness connector C-115 at ECM (M/T) or PCM harness connector C-118 at PCM (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  12 .
  9. Check for short circuit to ground between fuel gauge unit harness connector D-10 terminal No. 3 and ECM harness connector C-115 terminal No. 77 (M/T) or PCM harness connector C-118 terminal No. 51 (A/T). If wiring harness is in good condition, replace ECM or PCM. After replacing ECM or PCM, go to step  12 . If wiring harness is not in good condition, repair as necessary. After repairs, go to step  12 .
  10. 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  12 .
  11. Check intermediate connectors C-122, C-127 and D-14. Repair or replace as necessary. After repairs, go to next step. If intermediate connectors are okay, check for harness damage between fuel temperature sensor harness connector D-10 terminal No. 3 and ECM harness connector C-115 terminal No. 77 (M/T) or PCM harness connector C-118 terminal No. 51 (A/T). Repair or replace as necessary. After repairs, go to next step. If connectors are okay, replace ECM or PCM. After replacing ECM or PCM, go to next step.
  12. 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 P0181 is output, repeat diagnosis. If DTC P0181 is not output, inspection is complete.
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