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Home >> Audi >> 1991 >> 200 Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests >> Fuel Control (2.2L) >> OXS Frequency Valve
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OXS Frequency Valve

  1. Remove harness connector from OXS frequency valve. Connect LED Test Light (US 1115) 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 2.2L) under RETRIEVING CODES in TESTS W/CODES article in the ENGINE PERFORMANCE Section. When code appears, LED test light must be off. Replace OXS frequency valve if light is off but OXS frequency valve does not work.
  3. If light comes on, ensure battery voltage exists between OXS frequency valve terminal No. 1 (Blue/Black wire) and ground. Repair wiring or circuits if necessary.
  4. If battery voltage exists, 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 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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