Test Procedure

2005 Ford Taurus SEL, 4D SedanSECTION Test Procedure
WARNING: This page is about a different car, the 2011 Mercury Milan, 2011 Lincoln MKZ, 2011 Ford Fusion, 2010 Mercury Milan, and 2010 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.
  1. TC1 DIAGNOSTIC TROUBLE CODE (DTC) P0A23: VERIFY THE CONCERN IS PRESENT 
    • Record and clear all continuous memory DTCs.
    • Retrieve the PCM continuous memory DTCs.

    Is DTC P0A23 present? 

    Yes No
    GO to  TC2. GO to  TC7.
  2. TC2 CHECK THE TGAC CIRCUIT FOR AN OPEN CIRCUIT IN THE HARNESS 
    • Ignition OFF.
    • PCM connector disconnected.
    • Transaxle Assembly-B connector disconnected.
    • Measure the resistance between:
    RESISTANCE REFERENCE CHART

    (+) PCM Connector, Harness Side (-) Transaxle Assembly-B Connector, Harness Side
    TGAC - Pin B11 TGAC - Pin 9

    Is the resistance less than 5 ohms? 

    Yes No
    GO to  TC3. REPAIR the circuit.
    Clear the PCM DTCs. REPEAT the self-test.
  3. TC3 CHECK THE TGAC CIRCUIT FOR A SHORT TO VOLTAGE IN THE HARNESS 
    • Ignition ON, engine OFF.
    • Measure the voltage between:
    VOLTAGE REFERENCE CHART

    (+) PCM Connector, Harness Side (-) Vehicle Battery
    TGAC - Pin B11 Negative terminal

    Is the voltage less than 1 V? 

    Yes No
    GO to  TC4. REPAIR the circuit.
    Clear the PCM DTCs. REPEAT the self-test.
  4. TC4 CHECK THE TGAC CIRCUIT FOR A SHORT TO GROUND IN THE HARNESS 
    • Ignition OFF.
    • Measure the resistance between:
    RESISTANCE REFERENCE CHART

    (+) PCM Connector, Harness Side (-) Vehicle Battery
    TGAC - Pin B11 Negative terminal

    Is the resistance greater than 10K ohms? 

    Yes No
    GO to  TC5. REPAIR the circuit.
    Clear the PCM DTCs. REPEAT the self-test.
  5. TC5 CHECK FOR THE TGAC CIRCUIT SHORTED TO SIGNALS IN THE SAME HARNESS 
    • Measure the resistance between:
    RESISTANCE REFERENCE CHART

    (+) Transaxle Assembly-B Connector, Harness Side (-) Transaxle Assembly-B Connector, Harness Side
    TGAC - Pin 9 ISDN2 - Pin 7
    TGAC - Pin 9 GMSDN - Pin 5
    TGAC - Pin 9 CTO - Pin 1
    TGAC - Pin 9 TMAC - Pin 4

    Are the resistances greater than 10K ohms? 

    Yes No
    GO to  TC6. REPAIR the circuit.
    Clear the PCM DTCs. REPEAT the self-test.
  6. TC6 TGAC FUNCTIONAL TEST 
    • PCM connector connected.
    • Transaxle Assembly-B connector connected.
    • Isolate the TGAC pin from the Transaxle-B connector.
    • Connect a 5 amp fused jumper wire between the following:
      CONNECTOR PINS REFERENCE CHART

      Point A Transaxle Assembly-B Connector, Harness Side Point B Transaxle Assembly-B Connector, Harness Side
      TGAC - Pin 9 TMAC - Pin 4
    • Ignition ON, engine running.

    Does the engine start now? 

    Yes No
    INSTALL a new transaxle assembly. REFER to the ELECTRONICALLY CONTROLLED CONTINUOUSLY VARIABLE TRANSMISSION (ECVT) GO to  TC8.
  7. TC7 CHECK THE TGAC CIRCUIT FOR AN INTERMITTENT CONCERN 
    • Ignition ON, engine OFF.
    • Access the PCM and monitor the GTQ (TORQUE) PID.
    • Carefully wiggle all accessible wiring and connectors associated with the circuit and look for a change in the PID state.

    Is a concern present during the wiggle test? 

    Yes No
    REPAIR as necessary.
    Clear the PCM DTCs. REPEAT the self-test.
    GO to PINPOINT TEST Z .
  8. TC8 CHECK FOR CORRECT PCM OPERATION 
    • Disconnect all the PCM connectors.
    • Visually inspect for:
      • pushed out pins
      • corrosion
    • Connect all the PCM connectors and make sure they seat correctly.
    • Carry out the PCM self-test.
    • Verify the concern is still present.

    Is the concern still present? 

    Yes No
    INSTALL a new PCM.
    REFER to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) .
    The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.
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.

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.