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Matt, Mechanical Engineer
Category: UK Car
Satisfied Customers: 21631
Experience:  BEng hons Mech engineering, in auto industry 22 years
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Nisan micra 2003 no crank I have tested starter motor and

Customer Question

Nisan micra 2003 no crank I have tested starter motor and it's cranking OK still no start so I changed ecu and all body computers still no crank so tested the ignihon switch and that OK good now I am lost
Submitted: 1 year ago.
Category: UK Car
Expert:  Matt replied 1 year ago.


If the car's not cranking then first check it can turned over by hand so double checking for any mechanical issues

If OK then check that the main battery cables are on tight and the terminals are clean and bright. Do the same for the engine / gearbox earth strap.
Then follow the main positive lead back to the engine and down to the starter motor, and check the connection at this end as well.

There should also be a small wire to the motor which should have 12V when you're turning the ignition switch to crank. If the 12V isn't there, check back along this wire for damage to the insulation or corroded connections

This 12V feed comes directly from the ignition switch so this may be faulty and need replacing

Check the resistance of the main positive lead that runs down to the motor as anything more than a few ohms and it should be replaced

Don't forget to try a jump start from another car / battery as its possible the battery is poor, if you have a voltmeter a healthy battery should read 12.7+V

also try substituting the battery for another as I've known a very flat battery to drag down the system voltage too far even with jump cables

one other thing to consider is that the immobiliser is faulty and preventing the starter from being enabled - however if the dash / ignition lights are on then this usually means that its off

Customer: replied 1 year ago.
I have done all the checks on car replace the ecu and body computers from a working car and even changed the ignition switch and barel the starter motor is good and engine cranks good I have used a wire from battery to starter and engine cranks no start I am at a loss with car
Expert:  Matt replied 1 year ago.


Ok this really sounds like an issue with the security system

as if it won't crank on the key and it won't start when you give power to the starter motor

then it must be that the ECU isn't getting power and the starter circuit isn't being powered up

so I'd 1st suggest replacing the key-fob battery as the 1st step and if that doesn't help then sorry to say that the car will have to go to a dealer or nissan specialist to reset the body control unit

Customer: replied 1 year ago.
Ow well the body controls unit has been replaced with one out of working car and so has the ecu out of same working car do you no where I can get circlet diagram from for this stupid car lol thanks for your time
Expert:  Matt replied 1 year ago.


is this any good

Expert:  Matt replied 1 year ago.


do you still need help?

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