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Home >> Audi >> 2021 >> S8 >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Generic Scan Tool [CWWB,CXYA] (Diagnostic Procedures) >> St Generic Scan Tool >> Diagnosis And Testing >> Diagnostic Procedures >> Fuel Metering Valve - N290-, Checking

Fuel Metering Valve - N290-, Checking

General Description 

The Engine/Motor Control Module -J623- regulates the Fuel Metering Valve -N290- directly at the high pressure fuel pump to control the low pressure flow inside the high pressure fuel pump.

Special tools and workshop equipment required 

Test requirements 

Test Procedure 

Step Procedure Result / Action to Take
1
  • PERFORM: Preliminary Check to verify the customers complaint. Refer to PRELIMINARY CHECK .
-- Was Complaint verified?
-- YES:
  • GO TO: Step 2.
-- NO:
  • GATHER more information from customer about the complaint.
  • IGNITION: OFF.
  • DISCONNECT: Fuel Metering Valve -N290- harness connector.
  • CHECK: Fuel Metering Valve -N290- component connector terminals 1 to 2 for resistance.
  • SPECIFIED VALUE: 1.5 - 11 Ω (+/- 0.5 Ω @ approx. 20° C).
-- Was Value obtained?
-- YES:
  • GO TO: Step 3.
-- NO:
  • REPLACE: Fuel Metering Valve -N290-. Refer to appropriate Service Information.
  • GO TO: Step 4.
  • REMOVE: Engine/Motor Control Module - J623-. Refer to appropriate Service Information.
  • CHECK: Fuel Metering Valve -N290- harness connector terminal 1 to the Engine/Motor Control Module - J623- harness connector T56b / 56 for resistance.
  • CHECK: Fuel Metering Valve -N290- harness connector terminal 2 to the Engine/Motor Control Module - J623- harness connector T56b / 52 for resistance.
  • SPECIFIED VALUE: 0.5 Ω (± 0.3 Ω).
-- Were Values obtained?
-- YES:
  • TIP: The Fuel Metering Valve -N290- may fail under loaded operation; please swap a known good Fuel Metering Valve -N290- prior to continuing to the next step.
  • GO TO: Step 4.
-- NO:
  • PERFORM: Visual Inspection of wiring and component.
  • CHECK: Wiring for open, high resistance, short or harness connector for damage, corrosion, loose or broken terminals.
  • REPAIR: Faulty wiring or connector.
  • GO TO: Step 4.
  • Final Procedure 
  • Perform a road test to verify repair.
-- Does the original DTC return?
-- YES:
  • CHECK: Engine/Motor Control Module -J623- harness connector for any damaged, pushed-out pins.
  • REPAIR: As necessary.
  • If all electrical connections are OK:
  • REPLACE: Engine/Motor Control Module -J623-. Refer to appropriate Service Information.
  • Clear the DTC's. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
  • Repair is complete. Generate Readiness Code. Refer to READINESS CODE .
  • Return vehicle to Customer.
-- NO:
  • Perform the diagnostic procedure for any DTC's.
  • If no DTC's return, the repair is complete.
  • Return vehicle to customer.