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Home >> Audi >> 1990 >> 200 Base, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests >> Fuel System >> Fuel Control (Cis Digital Control) >> OXS Frequency Valve
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OXS Frequency Valve

  1. Disconnect harness connector from OXS frequency valve. Using LED Test Light (US 1115), connect Red lead to terminal No. 1 (Blue/Black wire). Connect Black lead to terminal No. 2 (Red wire).
  2. Perform steps in OUTPUT CODES (for CIS Digital Control) under RETRIEVING CODES in the G - TESTS W/ CODES article. When code appears, LED test light must be off. Replace OXS frequency valve if light is off and OXS frequency valve does not work.
  3. If light comes on, ensure 12 volts exist between OXS frequency valve terminal No. 1 (Blue/Black wire) and ground. Repair wiring or circuits as necessary.
  4. If 12 volts exist, turn ignition off. Disconnect ECU harness connector. Ensure resistance in wire between ECU terminal No. 8 and OXS frequency valve terminal No. 2 (Red wire) is approximately 10 ohms. See Figure for ECU terminal identifications. If resistance is not as specified, check for open circuit in wire. If wire is okay, replace ECU.
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