I pulled the plug from the pressure sensor and it was visibly corroded; cleaned it up.

I also found the test scenario on the WIS. With the engine running, pressure sensor electrically connected, and vacuum line disconnected: connect a voltmeter on pins 1 and 2. Voltage is supposed to be > 3.5v; Apply > 500mbars and voltage is supposed to be < 2v. Mine was in this range after I cleaned up the plug.

No codes or check engine light after a 5 mile drive; will see what happens this week.


as ever
Paul