SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSFORD2021TRANSIT-350 HD BASE, VAN CARGO EXTENDED, 3.5L ENG VIN 8, AWDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 13 (ENGINE CONTROLS - PINPOINT TESTS (DIESEL))PINPOINT TESTS FA: AMBIENT AIR TEMPERATURE (AAT) SENSORTEST PROCEDURE
2021 Ford Transit-350 HD Base, Van Cargo Extended, 3.5L Eng VIN 8, AWD

Test Procedure

2021 Ford Transit-350 HD Base, Van Cargo Extended, 3.5L Eng VIN 8, AWDSECTION Test Procedure
WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 2018 Ford Transit-350 HD, 2018 Ford Transit-350, 2018 Ford Transit-250, 2018 Ford Transit-150, and 2018 Ford F-550 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.
  • FA1 PRELIMINARY DIAGNOSIS 
    NOTE: Diagnose circuit DTCs before range or performance DTCs.

    Are DTCs P0070, P0071, P0072 or P0073 present? 

    Yes No
    GO to  FA2. RETURN to SYMPTOM CHARTS for further direction.
  • FA2 CHECK FOR AN OPEN 
    • Ignition OFF.
    • AAT Sensor connector disconnected.
    • For F-650/F-750,
    • PCM-B connector disconnected.
    • PCM-T connector disconnected.
    • Measure the resistance between:
      (+) AAT Sensor Connector, Harness Side (-) PCM-B Connector, Harness Side
      AAT AAT
    • Measure the resistance between:
      (+) AAT Sensor Connector, Harness Side (-) PCM-T Connector, Harness Side
      SIGRTN SIGRTN
    • For Transit,
    • PCM-T connector disconnected.
    • Measure the resistance between:
      (+) AAT Sensor Connector, Harness Side (-) PCM-T Connector, Harness Side
      AAT AAT
      SIGRTN SIGRTN
    • For all others,
    • PCM-B connector disconnected.
    • Measure the resistance between:
      (+) AAT Sensor Connector, Harness Side (-) PCM-B Connector, Harness Side
      AAT AAT
      SIGRTN SIGRTN

    Are the resistances less than 5 ohms? 

    Yes No
    GO to  FA3. REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test.
  • FA3 CHECK FOR A SHORT TO GROUND 
    • Measure the resistance between:
      (+) AAT Sensor Connector, Harness Side (-)
      AAT Ground
    • Measure the resistance between:
      (+) AAT Sensor Connector, Harness Side (-) AAT Sensor Connector, Harness Side
      AAT SIGRTN

    Are the resistances greater than 10K ohms? 

    Yes No
    GO to  FA4. REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test.
  • FA4 CHECK FOR A SHORT TO VOLTAGE 
    • Ignition ON, engine OFF.
    • Measure the voltage between:
      (+) AAT Sensor Connector, Harness Side (-)
      AAT Ground

    Is any voltage present? 

    Yes No
    REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test. GO to  FA5.
  • FA5 INTERMITTENT CHECK 
    • Ignition OFF.
    • AAT Sensor connector connected.
    • For Transit,
    • PCM-T connector connected.
    • For F-650/F-750,
    • PCM-B connector connected.
    • PCM-T connector connected.
    • For all others,
    • PCM-B connector connected.
    • Ignition ON, engine OFF.
    • Access the PCM and monitor the AAT_V (VOLT) PID.
    • While observing the PID, carry out the following:
    • Wiggle all accessible harness from the AAT sensor to the PCM and lightly tap on the sensor.
    • Wiggle the AAT sensor connector.
    • Look for sudden changes in the voltage when the harness and connector are wiggled or when the AAT sensor is tapped.

    Is a concern present? 

    Yes No
    REPAIR as necessary.
    Clear the PCM DTCs. REPEAT the self-test.    		 For DTCs P0072 or P0073, INSTALL a new AAT sensor.
    Clear the PCM DTCs. REPEAT the self-test.
    For all others, GO to  FA6.
  • FA6 TEMPERATURE SENSOR CORRELATION 
    NOTE: Check temperature values while engine is at ambient temperature, cold soak the engine for a minimum of 8 hours if necessary.
    • Ignition ON, engine OFF.
    • Access the PCM and monitor the AAT (TEMP), CAC_T (TEMP), ECT2_1 (TEMP) and EGRTC (TEMP) PIDs.
    • For Transit,
    • Access the PCM and monitor the IAT (TEMP) PID.
    • For all others,
    • Access the PCM and monitor the IAT11 (TEMP) PID.
    • The AAT temperature must be within the following ranges:
    • Within 10°C (18°F) degrees of the CAC_T reading
    • Within 15°C (27°F) degrees of the IAT (Transit) or IAT11 (all others) reading
    • Within 20°C (36°F) degrees of the ECT2_1 reading (F-650/F-750, F-Series Super Duty)
    • Within 16°C (28.8°F) degrees of the EGRTC reading

    Is the AAT PID within specification? 

    Yes No
    Unable to duplicate the condition. CHECK for a loose connection, and damaged or corroded terminals. WIGGLE the harness attempting to recreate the concern. REPAIR as necessary. INSTALL a new AAT sensor. REFER to the appropriate Climate Control article. Clear the PCM DTCs. REPEAT the self-test.
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

Shop Manual-Ready ToolsFree Quote CheckQuote Shield Pro

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.