Subject: Oxygen Sensor System Check   Models: 911/924/924 Turbo ALL

Bulletin Number: 80 – 02

When diagnosing poor engine operation, first perform a quick-check of the Oxygen Sensor System

Work procedure:

                Preliminary Conditions

• Engine in proper tune (ignition timing, idle speed etc.)
• No exhaust leaks
• Engine at operating temperature

• Connect Siemens 451 tester as follows:
• “+” lead to battery terminal or equivalent

• “-“ lead to OXS test connection No. II (marked on the back of plug)
• “%” button on test instrument pressed in
• Tester set for four cylinders

Note

When making OXS test, do not connect any other test leads. Ignore figures in “RPM” window.

• Note readings as follows:

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