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Help - NATS Fault on GUIII 4.2tdi

6869 Views 4 Replies 4 Participants Last post by  truckster
Arrived home last night and as i drove into the garage thought whats that red light (NATS security indicator) on the top of the dash doing on continuously, haven't noticed it before. Turned off the engine and the red light started flashing as usual. Went out today, truck started with out any problems and all was well until it came to getting home. Tried to start the truck and although it turned over it wouldn't start. Yep you guessed it, the NATS red light was on continuously. Had a quick look in the owners book qnd it says NATS fault. Great i thought, only bloody computer on the truck and it has to fail.

Tried the spare key but had the same result, NATS light flashing until the key is turned then goes to on continuous and won't start.

I manged to get the engine started by disconnecting the battery for 30 seconds to force a reset then started the truck. Whilst it started this time the light came on abouit 20 seconds later. When i got home i stopped the engine and tried to re-start and as you would expect it won't start.

I assume the NATS system prevents the fuel solenoid being energised.

Couple of questions for the GU guru's
1/ Is NATS something a local mechanic/auto electrician can fault find or do i need to see Mr Nissan.
2/ Does anyone know how to bypass the NATS system, i'm thinking a bypass switch straight onto the fuel solenoid positive wire but exactly where?. This is a pain in the neck when i'm at home but could be a real disaster if i was in the middle of the Simpson or similar.

Hope someone out there has seen this problem before and can offer some advice.

Thanks guys

Jez W
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There is a bit of info on this thread from a while ago

I think in the end the imobilizer unit was removed from the injector pump (2 shear bolts) & a switched power wire was connected directly to the fuel shut off solenoid (under the immobilizer unit)

Regards Don
Don is right, There is a code hopping solinoid on the injector pump that sits on top of the normal fuel cut solinoid.The code hopping one is held in by sheer bolts and has three wires going to it.Once removed the std solinoid has two wires. I think that you(to make it easier) will have to remoove the injector pump to enable you access to remoove the sheer bolts etc.hope this helps.
I think a quick visit to mr nissan to try and work out which part is faulty could be the answer, then take it from there.
Thanks for the replies guys. I went down to start the truck this morning and the red security light was on permanently when the ignition was turned to acc and of course the engine turned over but wouldn't start.

I've spent the morning checking all the wiring between the ignition key switch, the IMMU and the fuel pump solenoid (CSOLU) whilst the fault was present. I've finally tracked it down to a bad earth connection (black wire) inside the plug at the fuel pump. Looks like the previous owner was a bit heavy handed when it came to disconnecting the plug at some stage. Anyway, the NATS system is "smart" enough to detect an open circuit in the coded solenoid control circuits ie open circuit earth connection and prevents the engine from starting. Great idea Mr Nissan especially for those of us that spend a fair bit of time in remote areas!!

So problem solved but it has highlighted just how vulnerable even the mighty 4.2 is to electronic failure. I plan to get the coded solenoid block removed from the fuel pump at the first opportunity and just run with a traditional fuel cut off solenoid arrangement.

There's know way you would be able to bypass this NATS system if you were stuck out somewhere remote as the fuel pump has to be pulled off and the shear bolts drilled out, not a job i'd be keen to take on in the middle of the Canning Stock Route or similar.

Again thanks for the replies and hope this info helps some others at some stage, i'm sure i won't be the only one with a NATS problem.

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Gee this is one to print out and keep in the glovebox for when your 1/2way across the simpson..
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