A8 Quattro Sedan V8-4.2L (BGK) (2006)
Vehicle Speed Sensor Signal: Testing and Inspection
Speed Signal, Checking
Special tools, testers and auxiliary items required
‹› Multimeter (VAG1526) or Multimeter (VAG1715)
‹› Connector test kit (VAG1594)
‹› Wiring diagram
Test Prerequisites
‹› The respective fuses of Engine Control Module (ECM) (J623) must be OK:
‹› Battery voltage must be at least 11.5 Volts.
‹› Speedometer (G21) must be OK.
Test Sequence
CAUTION!
‹› Test and measuring equipment must always be secured to the rear seat and operated from there by a second person.
‹› If test and measuring equipment is operated from the passenger seat, the person seated there could be injured in the event of an
accident involving deployment of the passenger-side airbag.
‹› To test speed signal, vehicle must be driven. Doing this requires a second person.
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Connect diagnostic tester.
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Start engine and let run at idle.
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Under address word 33, select "Diagnostic mode 1: Checking measured values."
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Select the measuring value "PID 13: Vehicle speed".
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Perform a road test, and have the 2nd person observe the indication on the display.
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Check specified value of the vehicle speed:
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End diagnosis and switch ignition off.
If no speed is indicated:
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Check DTC memory.
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Read readiness code => [ Readiness Code, Reading ] See: Powertrain Management/Computers and Control Systems/Testing and
Inspection/Monitors, Trips, Drive Cycles and Readiness Codes. If DTC memory was erased, readiness code must be generated again => [
Readiness Code, Generating ] See: Powertrain Management/Computers and Control Systems/Testing and Inspection/Monitors, Trips, Drive
Cycles and Readiness Codes.