Oxygen (O2) Sensor Control
- Ensure engine coolant temperature is at least 176°F (80°C). Ensure idle speed is correct. Ensure there are no leaks between cylinder head and catalytic converter. Ensure voltage to oxygen (O2) sensor heater is okay. Turn ignition off.
- Connect Scan Tester (VAG 1551) to Data Link Connectors (DLC) located in center console, in front of shift lever. Start engine and let it idle. Press "1" to select RAPID DATA TRANSFER function.
- Press "0" and "1" buttons to select ENGINE ELECTRONICS function. Press "Q" button to enter input. Press right arrow button, then "0" and "8" buttons to select READ MEASUREMENT BLOCK function. Press "Q" button to enter input.
- Press "0" button twice to select INPUT DISPLAY GROUP NUMBER 00. Press "Q" button to enter input. Scan tester displays READ MEASUREMENT BLOCK 1 through 10.
- If channel No. 1 value is less than "63", read oxygen (O2) sensor signal in channel No. 6. Oxygen (O2) sensor signal must fluctuate. If signal fluctuates, press right arrow button. Press "0" and "6" button to select END OUTPUT function. Press "Q" button to enter output.
- If signal does not fluctuate, disconnect oxygen (O2) sensor 4-pin wiring harness connector located on right engine mount. See Fig 1
. Momentarily ground (20 seconds) Violet wire from wiring harness connector. Value displayed on channel 6 must increase.
- If value increased, replace oxygen (O2) sensor. Erase fault code(s). If value does not increase, check oxygen (O2) sensor circuit back to Electronic Control Module (ECM). Replace ECM if necessary. Erase fault code(s).
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