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Reducing Agent Injector -N474-, 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 

Start diagnosis

-- Disconnect theReducing Agent Injector -N474- electrical harness connector. -2-

Fig 1: Identifying Injector For Reducing Agent N474
GWWA26-10801Courtesy of AUDI OF AMERICA, LLC
NOTE:

The exhaust system MUST be at room temperature or the readings will be incorrect.

Checking resistance

-- Measure the resistance of the Reducing Agent Injector -N474- terminals.

Specified value: 12.4 Ω(+/- 1 Ω)

If the specified value was Not obtained replace the Reducing Agent Injector -N474-.

If the specified value was obtained:

Checking voltage

-- Turn the ignition switch ON.

-- Measure the voltage of the Reducing Agent Injector -N474- harness connector terminal 1 to ground.

Specified value: 11.20 V (+/- 1.5 V)

-- Measure the voltage of the Reducing Agent Injector -N474- harness connector terminal 2 to ground.

Specified value: 2.58 V (+/- 0.8 V)

If either of the specified values were Not obtained:

Checking wiring

-- Remove the Engine Control Module -J623-. Refer to the Repair Manual.

-- Using a multimeter, check the Reducing Agent Injector -N474- electrical harness connector to the Engine Control Module -J623- electrical harness T91 connector for resistance.

Reducing Agent Injector -N474- electrical harness connector terminal Engine Control Module -J623- electrical harness connector T91 terminals
1 91
2 74

Specified value: 1.5 Ω Max.

If the specified value was not obtained:

-- Check the wiring for a short circuit to each other, Battery voltage, Ground or high resistance.

-- If necessary, repair the faulty wiring connection.

-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.

If no malfunction is detected in the wiring and the voltage readings were Not correct:

-- Replace the Engine Control Module -J623-. Refer to the service information for removal and installation procedures.

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 .