A8 Sedan V8-3.7L (AEW) (1997)
Throttle Position Switch: Testing and Inspection
Closed Throttle Position (CTP) Switch, Checking
The CTP switch is located at the rear of the throttle body, at the Throttle Position (TP) sensor.
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Connect VAG1551 or VAG1552 Scan Tool (ST), and press buttons -0- and -1- to insert "Engine Electronics" address word 01 (engine running at
idle).
Indicated on display
Rapid data transfer
HELP
Select function XX
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Press buttons -0- and -8- to select "Read Measuring Value Block" function 08, and press -Q- button to confirm input.
Indicated on display
Read Measuring Value Block
Input display group number XXX
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Press buttons -0-, -0- and -4- to input display group number 4 (004), and press -Q- button to confirm input.
Indicated on display
Read Measuring Value Block 4
->
1
2
3
4
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Check specified values for basic functions at engine idle speed (display field 4):
Specified value in display field 4: "Idle"
If display does not change as described:
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Adjust accelerator pedal cable or linkage for cruise control.
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Check Throttle Position (TP) sensor for contamination.
If "Part throt" is displayed only after longer accelerator pedal travel:
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Adjust CTP switch.
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Briefly touch accelerator pedal (only a few millimeters).
Specified value: "Part throt"
If accelerator pedal cable adjustment is OK:
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Check CTP switch and wiring.
Checking Wiring
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Connect VAG1598/19 test box to ECM harness connector.