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Matt
Matt, Engineer - BEng Hons
Category: Porsche
Satisfied Customers: 21380
Experience:  Mechanical Engineer with 20 years experience in the auto industry, 8 yrs in formula 1 engine testing
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I have a 2002 porsche boxster s that will not crank when

Customer Question

I have a 2002 porsche boxster s that will not crank when trying to start. dash lights come on but nothing. i'm not sure but i left the top down on a rainy day and the inside got soaked. is there anything in the floor board the could have got shorted out?
Submitted: 1 year ago.
Category: Porsche
Expert:  Matt replied 1 year ago.

Hello

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

If this is all OK then its possible the car needs a new starter motor

Customer: replied 1 year ago.
Ever since i've had this issue, my switch that opens the hood doesn't work. I can open the truck just fine. Battery tender shows green, so the battery should be ok. I've manually turned the engine already so no problem there. It's got a brand new engine from porsche. I've heard alot of people having problems with the immobilizer even with the dash lights on.
Expert:  Matt replied 1 year ago.

Hello

there's an emergency release tucked away in the wheelarch to open the front hood

Customer: replied 1 year ago.
i've looked for the release once already, but i'll try again. I'll will be back in touch.
Expert:  Matt replied 1 year ago.

Good luck

Expert:  Matt replied 1 year ago.

Hi

do you still need help?

Bear in mind that the site takes a deposit from you at the beginning and this is held by the site until you rate my answer at which point the cash is split between the site and the expert. so if my answers have been helpful please rate my answer.

Customer: replied 1 year ago.
I still have not had a chance to work on my Porsche yet. As soon as I get my hood open to check my battery, we can continue to troubleshoot my original problem. Probably be Mon. or Tues.
Expert:  Matt replied 1 year ago.

understood

good luck

Customer: replied 1 year ago.
I was able to release to hood and replaced the battery with a new one. Still will not crank. there was no 12v going to the starter. the wire seemed ok. How to do troubleshoot the immobiliser?
Expert:  Matt replied 1 year ago.

1st thing to check is if the dash is lit up as normal with the ignition on

if it is then the immobilser is unlikely to be the problem

if the dash is not illuminated then yes the immobilser is not disarming

Customer: replied 1 year ago.
the dash does light up. I also read that the immobilser has caused issues even with the lights lit. Are there any electronics under the seat that could have shorted when the rain water soaked the inside?
Expert:  Matt replied 1 year ago.

OK

the box under the seat is the 'Control Unit anti-drive-off feature, Central Locking, Alarm System' so yes its quite possible being under water hasn't helped this.....

Replacement units are available, but you cannot reuse it once it's been coded to a particular car, meaning that you can't source it from a salvage yard as each one is coded to the car

I'd suggest disconnecting it 1st and use some contact / switch cleaner on the plug pins / contacts and also try bring the unit indoors and leave it somewhere warm to dry out overnight

if this doesn't help then sorry to say a new unit will be required

Expert:  Matt replied 1 year ago.

Hi

do you still need help?

Bear in mind that the site takes a deposit from you at the beginning and this is held by the site until you rate my answer at which point the cash is split between the site and the expert. so if my answers have been helpful please rate my answer.

Customer: replied 1 year ago.
This is what I uncovered. Do you think it could have damaged anything else?
Expert:  Matt replied 1 year ago.

hello

I'm surprised the fuse wasn't blown with damage

its possible that the main ECU has been damaged but you might have got away with it as the two units are fed with power independently and only exchange data

I'd say its time to get the car to a Porsche specialist or dealers in order to have a new box coded up to match your car

sorry to say that there's no DIY fix available to take this further as you need the dealer level diagnostic kit

Customer: replied 1 year ago.
is it possible to have the part repaired?
Customer: replied 1 year ago.
What are your thoughts on ECU Doctor?
Expert:  Matt replied 1 year ago.

I'd say it may be possible to repair it and yes a firm like ECU Doctor may be able to help

they will need to see the part however before being able to judge if its repairbale or not

also try these firms

http://www.ecudoctors.com/

http://stores.digitalautotech.com/StoreFront.bok