Rabbit L5-2.5L (BGQ) (2008)
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Oxygen Sensor: Testing and Inspection
Heated Oxygen Sensor, Checking
Heated Oxygen Sensor, Checking
Special tools, testers and auxiliary items required
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Multimeter
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wiring diagrams
NOTE: When servicing terminals in harness connector of Heated Oxygen Sensor (H02S) G39, use only gold-plated terminals.
Test requirements
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Fuse for Heated Oxygen Sensor (HO2S) G39 OK..
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Oxygen Sensor (O2S) Heater Z19 before catalytic converter OK, checking. See: Oxygen Sensor Heater Z19, Checking
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Battery voltage at least 12.5 volts.
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All electrical consumers such as, lights and rear window defroster, switched off.
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A/C switched off.
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Ground (GND) connections between engine/transmission/chassis OK.
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Exhaust system between catalytic converter and cylinder head properly sealed.
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Coolant Temperature at least 80 degrees C.
Test procedure
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Perform a preliminary check to verify the customers complaint. See: Computers and Control Systems/Testing and Inspection/Scan Tool Testing
and Procedures/Preliminary Check
Function test
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Perform the function test in Diagnostic Mode 06. See: Computers and Control Systems/Testing and Inspection/Scan Tool Testing and
Procedures/Diagnostic Mode 06 - Read Test Results For Specific Diagnostic Functions
If the specified values are not obtained:
Start diagnosis
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Check the electrical harness connector for damage, corrosion, loose or broken terminals.
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Disconnect the 6-pin electrical harness connector from the Heated Oxygen Sensor (HO2S) -G39-.
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Using a Multimeter, check the following wiring connections for an open circuit.
HO2S Sensor G39 electrical
Motronic Engine Control Module (ECM)
harness connector terminal
J623 electrical connector T121
terminal or test box socket
Pin 4
Fuse 21 (on fuse panel B)
Pin 3
5
Pin 6
70
Pin 2
51
Pin 1
52
Pin 5
71
Specified resistance 1.5 ohms max.
If the specification is not obtained:
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Check the wiring for a short circuit to Battery positive (+) or an open circuit.
