A4 Quattro Sedan L4-2.0L Turbo (CAEB) (2009)
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Test procedure
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Using a generic scan tool, refer to Diagnostic Mode 05 - Read Current System Data.
‹› Mode 05 may not be supported on all systems. On systems where Diagnostic Mode 05 is not supported, refer to Diagnostic Mode 6 for oxygen
sensor monitoring test results.
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Review the mode data test results.
If any of the test results indicate a monitor failure:
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Refer to the monitor support documentation as indicated in the mode test procedure to diagnose and repair the cause of the failure.
If the test results indicate no monitor failures:
Checking primary voltage
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Disconnect the oxygen sensor electrical harness connector.
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Switch ignition on.
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Using a multimeter, measure the voltage between the sensor signal and reference ground circuits.
‹› Specification: 0.400 to 0.500 V
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Switch ignition off.
If specified value is not obtained:
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Check the oxygen sensor wiring and connections.
If specified value is obtained:
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Replace the oxygen sensor.
Checking wiring and connections
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Remove the engine control module.
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Using a multimeter, measure the resistance of the signal and reference ground circuits between the oxygen sensor and the engine control module.
Refer to the applicable wiring diagram.
Specified value: 1.5 ohms max.
If the specification was not obtained:
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Check the circuits for a short to each other, short to battery voltage, and short to ground.
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Check the electrical harness connector for damage, corrosion, loose or broken terminals.
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Repair the wiring or connection as necessary.
If no malfunction is detected in the wiring:
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Replace the engine control module.
Final procedures
After 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 ] See: Testing and Inspection/Scan Tool Testing and
Procedures/Diagnostic Modes 01 - 09.
2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] See: Testing and Inspection/Scan Tool Testing
and Procedures/Diagnostic Modes 01 - 09.
