Audi Cars 1999-05

Throttle Position Sensor

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Testing



1.8L Engines

NOTE
The Throttle Position (TP) sensor is located inside the throttle valve control module.

When testing, ensure the throttle valve is in the closed throttle position, if necessary adjust accelerator pedal cable. Make sure the cruise control is properly adjusted and the power supply for throttle valve control module is OK.

  1. Connect a VAG 1551 or VAG 1552 scan tool and press buttons '0' and '1' to enter 'Engine Electronics: Address Word 01' (with ignition switched 'ON', but engine not running).
  2.  
  3. Press buttons '0' and '8' to select 'Read Measuring Value Block: Function 08'. Then, press the 'Q' button to confirm the proper input.
  4.  



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Fig. Showing display group field 3 for 'End Output: Function 06' (Audi A4 1.8L)

  1. Press buttons '0' and '6' to select 'End Output: Function 06', and then press the 'Q' button to confirm the input.
  2.  
  3. Switch the ignition off.
  4.  


NOTE
The values displayed in Display Field 3 depend on the calibration of the TP sensor and Do NOT correspond with the actual throttle valve opening in degrees. The maximum displayed value is 90°.

  1. If the throttle angle value does not increase uniformly, replace the throttle valve control module.
  2.  
  3. Carry out the adaptation of throttle valve control module to the ECM.
  4.  



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Fig. Indicating Display Field 3 readings (Audi A4 1.8L)

  1. Check the wiring by connecting a VAG 1598/22 test box to the ECM harness connector.
  2.  
  3. Connect a DMM, using the adapter cables from VW 1594 connector test kit.
  4.  
  5. Measure the wiring resistance to check for short circuit between the test box sockets 2 (Ground) and 75 (signal wire). The reading should be infinite ohms.
  6.  
  7. Now, switch the DMM to the voltage measuring range.
  8.  
  9. Switch ignition to 'ON'.
  10.  
  11. Check the wiring for short circuit to battery positive feed (B+).
  12.  
  13. Note the voltage reading, if applicable. If not, there should be zero volts.
  14.  
  15. Switch ignition to 'OFF'.
  16.  
  17. Continue the test, depending on whether or not voltage was measured.
  18.  



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Fig. Identifying the throttle valve control module 8-pin connector

  1. To continue with wiring testing, disconnect the 8-pin harness connector from the throttle valve control module.
  2.  

If the measured voltage in the previous test was approximately 5 volts, connect the DMM, using adapter cables from VW 1594 connector test kit.

  1. Measure resistance to check for any short circuit between test box sockets 62 (power supply) and 75 (signal wire). The DMM should show infinity.
  2.  
  3. If the measured voltage was approximately battery positive voltage , check the wiring at the 8-pin connector terminal 5 for short circuit to battery B+.
  4.  
  5. If there was no measured voltage, disconnect the 8-pin harness connector from the throttle valve control module.
  6.  
  7. Check the wiring for an open circuit between connector terminal 5 and the ECM test box socket 75 . The DMM should show a maximum resistance of 1.5 ohms.
  8.  
  9. If the wiring is OK, replace the throttle valve control module.
  10.  
  11. Carry out adaptation of the throttle valve control module to the ECM.
  12.  

2.8L
  1. Connect a VAG 1551/1552 scan tool.
  2.  
  3. Switch the ignition to 'ON', but Do NOT start the engine.
  4.  
  5. Press the '0' and '1' buttons to select 'Address Word 01: Engine Electronics.'
  6.  
  7. Press the '0' and '8' buttons to select 'Function 08: Read Measuring Value Block'
  8.  
  9. Press the 'Q' button to enter input.
  10.  
  11. Press the '0', '0' and '2' buttons to select 'Display Group 2.'
  12.  
  13. Press the 'Q' button to enter input.
  14.  



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Fig. Identifying the TP sensor on Audi A4 with 2.8L engine

  1. To check wiring resistance, switch the DMM to measure Ohms Resistance. Connect the DMM between terminals 1 and 2 . The DMM should read 1,500 to 2,600 ohms.
  2.  
  3. Now, measure the resistance between terminals 2 and 3 . It should be, at closed throttle, approximately 750 to 1,300 ohms.
  4.  
  5. Slowly move the throttle from the closed throttle position to wide-open throttle position. Now the specification should show the resistance increasing gradually from closed throttle to WOT, where it should reach a maximum of 3,600 ohms.
  6.  
  7. If any one of the specified values is not obtained, replace the throttle position sensor.
  8.  
  9. To check the voltage supply to the TP sensor, disconnect TP sensor harness connector.
  10.  
  11. Switch the ignition 'ON', but Do NOT start the engine.
  12.  



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Fig. Showing the TPS connector for Audi A4 2.8L

  1. Switch the DMM to measure 'volts' and connect the DMM, in sequence, between terminals 1 (B+) and 2 (GND) and take a reading.
  2.  
  3. Then connect the DMM, in sequence, between terminals 1 (B+) and 3 (signal) and take a voltage reading.
  4.  
  5. In both cases the DMM should show 4.5 to 5.5 volts.
  6.  
  7. If neither check provides the specified value, recheck the TP sensor resistance as described previously. If the specified values are not obtained, check the ECM wiring as follows:
  8.  
    1. Connect the VAG 1598/19 test box to the ECM harness connector.
    2.  
    3. Check the ground (GND) wire for continuity between the TP sensor connector terminal 2 and test box socket D12 .
    4.  
    5. The test box should show a maximum of 1 ohm.
    6.  
    7. Check the B+ wire for continuity between the TP sensor connector terminal 1 and test box socket A3 .
    8.  
    9. The specification should show a maximum 1 ohm.
    10.  
    11. Check the signal wire for continuity between the TP sensor connector terminal 3 and test box socket A24 . The specification should be a maximum 1 ohm.
    12.  

  9. If the specified value is not obtained, determine if an open or short circuit exists in wiring, using a wiring diagram. Repair as necessary.
  10.  


NOTE
If it becomes necessary to repair or replace any of the throttle position sensor electrical terminals, ONLY replace with gold-plated terminals.

  1. If the wiring is OK, replace the ECM.
  2.  

 
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