dr914

Please can anyone comment on the reason for a 1 amp battery drain on fuse c1 engine electronics 2004 boxster?

Macster

The engine controller is "alive", that is powered up/active at least to some extent. (Fully active the draw can be more than 1 amp.)

How are you measuring this draw? For how long are you measuring this?

It can take some time after one shuts of the doors and locks the car before the engine controller and other electronics are in their lowest power state.

While my 2002 Boxster goes into a pretty low power mode almost immediately after I lock the car my 2003 Turbo continues to draw some considerable amperage -- I don't recall the amount now but it is quite a bit -- for some time after the engine is shut off, the key removed from the ignition, the doors closed and the car locked. Part of this arises from something (the engine controller most likely) monitoring engine compartment temperature and turning on the engine compartment fan if the temperature climbs too high. My Turbo's engine compartment fan can run even if the car is locked. I believe your 2004 can also run the engine compartment fan with the car locked. My Boxster can only run the fan if the car is left unlocked. If I lock the car I don't believe I have ever noticed the engine compartment fan coming on even in extremely high ambient temperatures.

mikefocke

How long after the key is removed? Car locked? What were the circumstances before the key was removed?

dr914

Car locked, car sitting there, next day ammeter between neg cable and post, draws .4 amps, If we remove c-1 drops to .02 amps. Should be .05 or less I would think. Hence c1 circuit is the problem. Thanks for the guidance

mikefocke

Measure pre-02 after 31 minutes, '02 and later after 61. C1 - engine electronics

dr914

Thank you, It never goes away. Question is, what is on that circuit that could cause a constant drain like we have

dr914

found it Mis plugged wire in the rear trunk under the carpeted cover, someone had switched to a different pin location