Quote Originally Posted by the evil twin View Post
You can also measure the continuity of the solenoid to see if it is burnt out but I can't remember what it is supposed to be, sorry.
I can probably find this spec if you want to test it. Recently solved a very frustrating problem with ours (randomly losing 1st and 4th gear), and I learnt how to use the AT section of the Nissan workshop manual fairly well.

Quote Originally Posted by the evil twin View Post
Well, the following depends on how much fault finding you want to do but...

Access the Tranny ECU behind the passenger kick panel.
Locate pin 22 and strip a bit of insulation back then using either a multi-meter or an LED or test lamp take the vehicle for a drive.
The solenoid power should appear on pin 22 (above 85 kph etc etc) if it doesn't then it is an input IE, Temp, TPS, Speed etc
If the power is there above 80ish KPH then it is a transmission issue IE lock up solenoid or whatever
This would work well in narrowing down what needs testing, as would a manual lock up system.
Ours wont stay locked in with the TCU computer, but when I hit the switch myself it works every time.