nissan x-trail only starts when jumped (spark plugs, engine, battery, sensor)

[leo_nava]

Hi, I have a Nissan X-trail 2005 SE. It only starts when jumped. My mechanic just put in a new battery, starter motor, spark plugs, and cam shaft sensor. The alternator was also replaced last year. The problem still persists (especially during winter), any idea why? Thanks!

[ukrkoz]

You do not have enough power supply from battery to the starting system. Something inbetween is high resistance stealing power.
First things to check is battery terminals and cables condition. they must be perfectly clean, lubricated and sealed. There should be no loose or rust in cables where they connect with clamps. Bad connection there is a very common culprit.
You need to check alternator output to the battery too.
Check belt tension. loose belt=under performing alternator.

[Iam4USC]

Change the battery terminals and tighten well.

[engineman]

Check that you have good ground cable connections between the engine and body/frame. The engine mounts are rubber, an excellent insulator. Half of any circuit is the ground, a bad ground connection is the same as an open switch.

An X-Trail tells me you are probably in Canada. You could have salt corrosion at the above mentioned connections.