Porsche Boxster 986 (1998 Base) D-4/P-4 issue - Fixed

Had this blinking D-4 and P-4 issue from the time I acquired the unit. Took me more than a month to figure out the problem.

Had done change of transmission fluid, clean transmission filter, cleaned the transmission signal cables and connectors, change the orif coolant valve as advised by enthusiast and member of boxsters club around the globe but it is not fixed.

After 2 weeks of researching again and thinking what could have been wrong , I thought of tracing power supply of the vacuum controllers and found that the wire for the vacuum of the transmission valve was cut and seems to be chewed by a rodent. I desparately look for the other end and after 2 days of tracing, i though of cutting the wire harness as I noticed it was tampered. There i found the other end, hidden underneath the tape, purposely hidden. The mechanic of the previous owner might have hide it for whatever reason.

I just connected the wires, soldered them and put them back in the harness. No more D-4/P-4 issue after. Coolant valve works fine and operating temperature has been normal ever since.

#986 #boxster #porsche