Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1986 Porsche 944 Base, AutomaticFACTORY OEM SERVICE PROCEDURE
High Altitude Switch
- Locate the high altitude switch on left instrument panel. Disconnect the altitude switch plug. Connect an ohmmeter to switch terminals. The altitude switch should be open under 3300 ft. (1000 m).
- Warm engine to operating temperature. Disconnect the oxygen sensor. Disconnect the high altitude switch. Remove vacuum hose from the fuel pressure regulator and plug.
- Connect an exhaust gas analyzer to the exhaust pipe. Operate engine at 2000 RPM and note CO% level.
- Bridge the high altitude switch harness terminals. At 2000 RPM, CO% level should be leaner. If not, check high altitude connectors. Ensure continuity of one wire to ground. The other wire should have continuity to CU terminal No. 28.
Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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