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Home >> Lincoln >> 2020 >> MKZ Base, AWD >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Controls - Pinpoint Test KF: Fan Control Relays Through Pinpoint Test Z: Intermittent - (Except Diesel & Hybrid) >> Pinpoint Test RB: Exhaust Gas Temperature (EGT) Sensor >> Test Procedure
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Test Procedure

  1. RB1 PRELIMINARY DIAGNOSIS 

    Are DTCs P0544, P0545, P0546, P0547, P0548 or P0549 present? 

    Yes No
    GO to  RB2. RETURN to SYMPTOM CHARTS for further direction.
  2. RB2 CHECK FOR LEAKS IN THE EXHAUST SYSTEM 
    • Ignition OFF.
    • Visually inspect the exhaust system for the following:
      • exhaust leaks at flanges and gaskets
      • punctures or cracks in the catalyst
      • punctures or cracks in the particulate filter
      • engine coolant or oil contamination

    Is a concern present? 

    Yes No
    REPAIR as necessary.
    Clear the PCM DTCs. REPEAT the self-test.    		 GO to  RB3.
  3. RB3 CHECK THE EGT SIGNAL AND SIGRTN CIRCUITS FOR AN OPEN 
    • Ignition OFF.
    • For the EGT11 sensor,
    • EGT11 Sensor connector disconnected.
    • PCM connector disconnected.
    • Measure the resistance between:
      (+) EGT11 Sensor Connector, Harness Side (-) PCM Connector, Harness Side
      EGT11 EGT11
      SIGRTN SIGRTN
    • For the EGT21 sensor,
    • EGT21 Sensor connector disconnected.
    • PCM connector disconnected.
    • Measure the resistance between:
      (+) EGT21 Sensor Connector, Harness Side (-) PCM Connector, Harness Side
      EGT21 EGT21
      SIGRTN SIGRTN

    Are the resistances less than 5 ohms? 

    Yes No
    GO to  RB4. REPAIR the open circuit. Clear the PCM DTCs.
    REPEAT the self-test.
  4. RB4 CHECK THE EGT SIGNAL CIRCUIT FOR A SHORT TO GROUND OR SIGRTN 
    • For the EGT11 sensor,
    • Measure the resistance between:
      (+) EGT11 Sensor Connector, Harness Side (-)
      EGT11 Ground
    • Measure the resistance between:
      (+) EGT11 Sensor Connector, Harness Side (-) EGT11 Sensor Connector, Harness Side
      EGT11 SIGRTN
    • For the EGT21 sensor,
    • Measure the resistance between:
      (+) EGT21 Sensor Connector, Harness Side (-)
      EGT21 Ground
    • Measure the resistance between:
      (+) EGT21 Sensor Connector, Harness Side (-) EGT21 Sensor Connector, Harness Side
      EGT21 SIGRTN

    Is the resistance greater than 10K ohms? 

    Yes No
    GO to  RB5. REPAIR the short circuit. Clear the PCM DTCs.
    REPEAT the self-test.
  5. RB5 CHECK THE EGT SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE 
    • Ignition ON, engine OFF.
    • For the EGT11 sensor,
    • Measure the voltage between:
      (+) EGT11 Sensor Connector, Harness Side (-)
      EGT11 Ground
      SIGRTN Ground
    • For the EGT21 sensor,
    • Measure the voltage between:
      (+) EGT21 Sensor Connector, Harness Side (-)
      EGT21 Ground
      SIGRTN Ground

    Is any voltage present? 

    Yes No
    REPAIR the short circuit. Clear the PCM DTCs.
    REPEAT the self-test.    		 GO to  RB6.
  6. RB6 CHECK THE EGT SENSOR AND CIRCUITS FOR AN INTERMITTENT SHORT OR OPEN 
    NOTE: If any EGT sensor connector has been disconnected during testing, with the ignition ON and the engine OFF, connect the EGT sensor. Turn the ignition OFF for 30 seconds before attempting to start the vehicle. Do not crank or start the engine until the ignition has been turned OFF for a minimum of 30 seconds. Failure to do so may result in a 60 minute no crank, no start condition and a failure mode effects management (FMEM) condition.
    • Ignition OFF.
    • For the EGT11 sensor,
    • EGT11 Sensor connector connected.
    • PCM connector connected.
    • Ignition ON, engine running.
    • Allow the engine to reach normal operating temperature.
    • Access the PCM and monitor the EGT11 (TEMP) PID.
    • Record the EGT11 (TEMP) PID.
    • Set the scan tool EGT11 (TEMP) PID limit as follows:
      • set the lower limit to 30°C (54°F) below the EGT11 (TEMP) PID.
      • set the upper limit to 20°C (36°F) above the EGT11 (TEMP) PID.
    • Carry out a thorough wiggle test on the EGT11 harness from the PCM connector to the EGT11 sensor connector.
    • Tap lightly around the sensor to simulate road shock.
    • For the EGT21 sensor,
    • EGT21 Sensor connector connected.
    • PCM connector connected.
    • Ignition ON, engine running.
    • Allow the engine to reach normal operating temperature.
    • Access the PCM and monitor the EGT21 (TEMP) PID.
    • Record the EGT21 (TEMP) PID.
    • Set the scan tool EGT21 (TEMP) PID limit as follows:
      • set the lower limit to 30°C (54°F) below the EGT21 (TEMP) PID.
      • set the upper limit to 20°C (36°F) above the EGT21 (TEMP) PID.
    • Carry out a thorough wiggle test on the EGT21 harness from the PCM connector to the EGT21 sensor connector.
    • Tap lightly around the sensor to simulate road shock.

    Does the EGT11 (TEMP) PID value or the EGT21 (TEMP) PID exceed the set limits range? 

    Yes No
    REPAIR as necessary.
    Clear the PCM DTCs. REPEAT the self-test.    		 GO to  RB7.
  7. RB7 CHECK THE EGT SENSOR PERFORMANCE 
    NOTE: An EGT sensor may exceed its operating range only while in regeneration mode, which may result in performance DTCs being set.
    • Access the PCM and monitor the EGT11 (TEMP) PID and the EGT21 (TEMP) PID.
    • Drive the vehicle at several steady state speeds above and below 50 km/h (30 mph). Monitor the EGT11 and EGT21 PID while driving to verify the concern.

    Does the EGT11 or the EGT21 temperature ever exceed 950°C (1740°F)? 

    Yes No
    CHECK the circuits for corrosion or loose wires. WIGGLE the harness attempting to recreate the concern. REPAIR as necessary.
    Clear the PCM DTCs. REPEAT the self-test.    		 GO to  RB8.
  8. RB8 CHECK THE EGT SENSOR FOR CORRECT RESISTANCE 
    • Ignition OFF.
    • For the EGT11 sensor,
    • EGT11 Sensor connector disconnected.
    • Measure the resistance between:
      (+) EGT11 Sensor Connector, Component Side (-) EGT11 Sensor Connector, Component Side
      EGT11 SIGRTN
    • For the EGT21 sensor,
    • EGT21 Sensor connector disconnected.
    • Measure the resistance between:
      (+) EGT21 Sensor Connector, Component Side (-) EGT21 Sensor Connector, Component Side
      EGT21 SIGRTN

    Is the resistance greater than 80 ohms? 

    Yes No
    GO to  RB9. INSTALL a new EGT sensor. REFER to the Electronic Engine Controls article.
    Clear the PCM DTCs. REPEAT the self-test.
  9. RB9 CHECK FOR CORRECT EGT SENSOR OPERATION 
    • Ignition ON, engine OFF.
    • For the EGT11 sensor,
    • Access the PCM and monitor the EGT11_V (VOLT) PID.
    • For the EGT21 sensor,
    • Access the PCM and monitor the EGT21_V (VOLT) PID.

    Is the EGT11 sensor or the EGT21 PID value greater than 4.7 V when disconnected? 

    Yes No
    The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CHECK for a loose connection, and damaged or corroded terminals. WIGGLE the harness attempting to recreate the concern. REPAIR as necessary. If no concerns were found during the visual inspection, INSTALL a new EGT sensor. REFER to the Electronic Engine Controls article.
    Clear the PCM DTCs. REPEAT the self-test.
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