Aura, Outlook 2007

Throttle Actuator Control System

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Throttle Actuator Control Module



Operation

The Throttle Actuator Control (TAC) system uses 2 Throttle Position (TPS) sensors to monitor the throttle position. The TP sensors 1 and 2 are located within the throttle body assembly. Each sensor has the following circuits:



A 5-volt reference circuit
 
A low reference circuit
 
A signal circuit
 

Two processors are also used to monitor the TAC system data. Both processors are located within the Engine Control Module (ECM). Each signal circuit provides both processors with a signal voltage proportional to throttle plate movement. Both processors monitor each other's data to verify that the indicated TP calculation is correct.

Removal & Installation
2.4L Engine

NOTE
Do not use solvent of any type when cleaning the gasket surfaces on the intake manifold and the throttle body assembly, as damage to the gasket surfaces and throttle body assembly may result. Use care in cleaning the gasket surfaces on the intake manifold and the throttle body assembly, as sharp tools may damage the gasket surfaces.


NOTE
Do not use any solvent that contains Methyl Ethyl Ketone (MEK). This solvent may damage fuel system components.


NOTE
DO NOT prop open the throttle blade with the ignition key in the ON position as it may set a Diagnostic Trouble Code (DTC).

  1. Remove the air cleaner outlet duct.
  2.  
  3. Disconnect the engine wiring harness electrical connector from the Electronic Throttle Control (ETC).
  4.  
  5. Remove the throttle body bolts.
  6.  
  7. Remove the throttle body .
  8.  
  9. Inspect the throttle body gasket, and replace if necessary.
  10.  

To install:

  1. Install the throttle body. Tighten the bolts to 89 in. lbs. (10 Nm).
  2.  
  3. Connect the engine wiring harness electrical connector to the ETC.
  4.  
  5. Install the air cleaner outlet duct
  6.  

3.5L Engine

NOTE
Do not use solvent of any type when cleaning the gasket surfaces on the intake manifold and the throttle body assembly, as damage to the gasket surfaces and throttle body assembly may result. Use care in cleaning the gasket surfaces on the intake manifold and the throttle body assembly, as sharp tools may damage the gasket surfaces.

  1. Remove the intake manifold cover.
  2.  
  3. Remove the air cleaner outlet duct.
  4.  
  5. Disconnect the engine wiring harness electrical connector from the Electronic Throttle Control (ETC).
  6.  
  7. Remove the heater inlet and outlet pipe nuts.
  8.  
  9. Remove the heater inlet and outlet pipe bracket from the throttle body studs. Reposition the pipes aside.
  10.  
  11. Remove the throttle body bolts and nuts.
  12.  
  13. Remove the throttle body.
  14.  
  15. Remove and discard the throttle body gasket.
  16.  

To install:

  1. Clean the gasket mating surfaces.
  2.  
  3. Install a new gasket.
  4.  
  5. Install the throttle body. Tighten the bolts and nuts to 89 in. lbs. (10 Nm).
  6.  
  7. Reposition the heater inlet and outlet pipes and install the pipe bracket to the throttle body studs. Tighten the nuts to 89 in. lbs. (10 Nm).
  8.  
  9. Connect the engine wiring harness electrical connector to the ETC.
  10.  
  11. Install the air cleaner outlet duct.
  12.  
  13. Install the intake manifold cover.
  14.  
  15. Perform the Throttle Learn Procedure as follows:
    1. Start and idle the engine in PARK for 3 minutes.
    2.  
    3. With a scan tool, monitor desired and actual RPM.
    4.  
    5. The ECM will start to learn the new idle cells and Desired RPM should start to decrease.
    6.  
    7. Turn the ignition OFF for 60 seconds.
    8.  
    9. Start and idle the engine in PARK for 3 minutes.
    10.  
    11. After the 3 minute run time the engine should be idling normal.
      NOTE
      During the drive cycle the check engine light may come on with idle speed DTCs. If idle speed codes are set, clear codes so the ECM can continue to learn. If the engine idle speed has not been learned the vehicle will need to be driven at speeds above 70 km/h (44 mph) with several decelerations and extended idles.

    12.  
    13. After the drive cycle, the engine should be idling normally. If the engine idle speed has not been learned, turn OFF the ignition for 60 seconds repeat the throttle learn procedure.
    14.  
    15. Once the engine speed has returned to normal, clear DTCs.
    16.  

  16.  

3.6L Engine
  1. Remove the air cleaner outlet duct.
  2.  
  3. Disconnect the engine wiring harness electrical connector from the Electronic Throttle Control (ETC).
  4.  
  5. Remove the throttle body bolts.
  6.  
  7. Remove the throttle body and gasket. Discard the gasket.
  8.  

To install:

  1. Clean the gasket mating surfaces.
  2.  
  3. Install a new gasket.
  4.  
  5. Install the throttle body. Tighten the bolts to 89 in. lbs. (10 Nm).
  6.  
  7. Connect the engine wiring harness electrical connector to the ETC.
  8.  
  9. Install the air cleaner outlet duct.
  10.  
  11. Perform the Throttle Learn Procedure as follows:
    1. Start and idle the engine in PARK for 3 minutes.
    2.  
    3. With a scan tool, monitor desired and actual RPM.
    4.  
    5. The ECM will start to learn the new idle cells and Desired RPM should start to decrease.
    6.  
    7. Turn the ignition OFF for 60 seconds.
    8.  
    9. Start and idle the engine in PARK for 3 minutes.
    10.  
    11. After the 3 minute run time the engine should be idling normal.
      NOTE
      During the drive cycle the check engine light may come on with idle speed DTCs. If idle speed codes are set, clear codes so the ECM can continue to learn. If the engine idle speed has not been learned the vehicle will need to be driven at speeds above 70 km/h (44 mph) with several decelerations and extended idles.

    12.  
    13. After the drive cycle, the engine should be idling normally. If the engine idle speed has not been learned, turn OFF the ignition for 60 seconds repeat the throttle learn procedure.
    14.  
    15. Once the engine speed has returned to normal, clear DTCs.
    16.  

  12.  

Testing
2.4L Engine


Click image to see an enlarged view

Fig. Throttle Actuator Control (TAC) terminals-2.4L engine (A) TAC Motor Control - 2 (B) TAC Motor Control - 1 (C) Low Reference (D) TP Sensor 1 Signal (E) 5-Volt Reference 2 (F) TP Sensor 2 Signal


CAUTION
Turn OFF the ignition before inserting fingers into the throttle bore. Unexpected movement of the throttle blade could cause personal injury.

  1. Inspect the throttle body for:
    NOTE
    Disconnecting the throttle body harness connector causes additional DTCs to set.



    A throttle blade that is NOT in the rest position
     
    A throttle valve that is binding open or closed
     
    A throttle valve that is free to move open or closed WITHOUT spring pressure
     

  2.  
  3. Turn the ignition OFF, disconnect the harness connector at the throttle body.
  4.  
  5. Turn the ignition ON, test for 0 volts between each motor control circuit terminal E and F and ground. If greater than 0 volts, test the affected motor control circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  6.  
  7. Turn the ignition ON, verify that a test lamp does not illuminate between each motor control circuit terminal E and F and B+. If test lamp illuminates, test the affected motor control circuit for a short to ground. If the circuit tests normal, replace the ECM.
  8.  
  9. Turn the ignition OFF, allow sufficient time for the ECM to completely power down. Connect a DMM between the motor control 1 circuit terminal E and ground. Using the peak min max function measure for ignition voltage on the motor control 1 circuit as the ignition is turned ON. If voltage is not within 1 volt of ignition voltage, test for an open or high resistance. If the circuit tests normal, replace the ECM.
  10.  
  11. Turn the ignition OFF, allow sufficient time for the ECM to completely power down. Connect a DMM between the motor control 2 terminal F circuit and ground.
  12.  
  13. Using the peak min max function, measure the voltage on the motor control 2 circuit as the ignition is turned ON. Voltage should be within 1 volt of ignition voltage. If voltage is not within 1 volt of ignition voltage, test for an open or high resistance. If the circuit tests normal, replace the ECM.
  14.  
  15. If all circuits test normal, replace the throttle body.
  16.  

3.5L And 3.6L Engines
  1. Turn the OFF, disconnect the harness connector at the throttle body.
  2.  
  3. Turn the OFF for 90 seconds, test for less than 5 ohms of resistance between the low reference circuit terminal C and ground. If greater than 5 ohms, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  4.  
  5. Turn the ON, test for 4.8-5.2 volts between 5-volt reference circuit terminal E and ground. If less than 4.8 volts, test 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM. If greater than 5.2 volts, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  6.  
  7. Verify the scan tool TP sensor 1 voltage is less than 0.1 volt. If greater than 0.1 volt, test the signal circuit terminal D for a short to voltage. If the circuit tests normal, replace the ECM.
  8.  
  9. Verify the scan tool TP sensor 2 voltage is greater than 4.8 volts. If less than 4.8 volts, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM.
  10.  
  11. Install a 3A fused jumper wire between the signal circuit terminal D and the 5-volt reference circuit terminal E of the TP sensor 1. Verify the TP sensor 1 voltage is greater than 4.8 volts. If less than 4.8 volts, test the TP sensor 1 signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
  12.  
  13. Install a 3A fused jumper wire between the signal circuit terminal F and the low reference circuit terminal C of the TP sensor 2. Verify that the TP sensor 2 voltage is less than 0.1 volt. If greater than 0.1 volt, test the TP sensor 2 signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
  14.  
  15. Turn the OFF for 90 seconds, disconnect the harness connector at the ECM.
  16.  
  17. Test for less than 5 ohms of resistance on all TP sensor circuits between the following terminals:

    ECM C2 signal circuit terminal 64 to TP terminal D
     
    ECM C2 signal circuit terminal 66 to TP terminal F
     
    ECM C2 5-volt reference circuit terminal 44 to terminal E
     

  18.  
  19. If greater than 5 ohms, repair the affected circuit for open/high resistance.
  20.  
  21. Test for infinite resistance between TP sensor 1 signal circuit terminal D and TP sensor signal circuit terminal F. If less than infinite resistance, repair the short between TP sensor 1 signal circuit and TP sensor 2 signal circuit.
  22.  
  23. If all circuits test normal, replace the throttle body.

    Click image to see an enlarged view

    Fig. Throttle Actuator Control (TAC) Module terminals-3.5L and 3.6L engines (A) TAC Motor Control - 2 (B) TAC Motor Control - 1 (C) Low Reference (D) TP Sensor 1 Signal (E) 5-Volt Reference 2 (F) TP Sensor 2 Signal

  24.  

 
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