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Home >> Audi >> 2012 >> Q7 3.0 TDI >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> 3.0L - Generic Scan Tool - Engine Code: CATA >> St Generic Scan Tool >> Diagnosis And Testing >> Diagnostic Procedures >> Speed Signal, CHECKING
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Speed Signal, CHECKING

Observe all safety precautions: SAFETY PRECAUTIONS 

View clean working conditions: CLEAN WORKING CONDITIONS 

Prior to repair work, perform a preliminary check to verify the condition. Refer to PRELIMINARY CHECK .

Use only gold-plated terminals when servicing any component with gold-plated electrical harness connector terminals.

For wiring diagrams, component locations, and connector views, Refer to the applicable wiring diagram.

Special tools and workshop equipment required 

Test Requirements 

Function test

-- Connect the scan tool.

-- Perform a road test with a vehicle speed greater than 5 Km/h.

-- Using the scan tool, Check the vehicle speed:

Diagnostic text Specified value
Vehicle Speed Approx. Vehicle Speed

-- Compare the vehicle speed on the scan tool to the Speedometer -G21-.

Specified value: a difference of no greater than 10%.

If the specified value was not obtained or no speed was displayed:

-- Check the wiring from the Engine Control Module -J623- electrical harness connector to the Instrument Cluster Control Module -J285- for an open circuit, Short to Battery (+), or to Ground. Refer to Wiring Diagram.

-- Check the wiring connection for damage, corrosion, loose or broken terminals.

-- If necessary, repair the faulty wiring connection.

Final Procedures 

After the repair work, the following work steps must be performed in the following sequence:

  1. Check the DTC memory. Refer to DIAGNOSTIC MODE 03 - READ DTC MEMORY .
  2. If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
  3. If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .