1999 NATS Failure - again -? '98 ECU swap?
11-14-2007, 06:52 PM
#1
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1999 NATS Failure - again -? '98 ECU swap?
I went to start my '99 4.5 gen Max this morning, and the engine starts right up, then dies - and stays dead. The starter cranks, but no ignition. Bummer. 
Took my pickup to work, and looked at the car tonight.
For the third time in a year, the NATS barfed on itself and the car won't start until I trailer it over to a local dealer for a up-close-and-personal visit with the Consult.
I have another '99 Infiniti automatic ECU and a '98 maxima automatic ECU. Does anyone know - for sure - that the '98 ECU will plug in and work in my automatic? I don't care about minor codes - I've got a 443 and 1105 which should be fixable, with some time - although while under the car swearing at the eBrake cables, I saw that someone had stolen the EVAP canister and the lid. That might be the 443.
The car has been starting easily and running great up to now.
Yes, I've searched the ORG and didn't find anything. I'm almost sure that I've seen a reference to this before, but ????
Took my pickup to work, and looked at the car tonight. For the third time in a year, the NATS barfed on itself and the car won't start until I trailer it over to a local dealer for a up-close-and-personal visit with the Consult.
I have another '99 Infiniti automatic ECU and a '98 maxima automatic ECU. Does anyone know - for sure - that the '98 ECU will plug in and work in my automatic? I don't care about minor codes - I've got a 443 and 1105 which should be fixable, with some time - although while under the car swearing at the eBrake cables, I saw that someone had stolen the EVAP canister and the lid. That might be the 443.
The car has been starting easily and running great up to now.
Yes, I've searched the ORG and didn't find anything. I'm almost sure that I've seen a reference to this before, but ????
11-15-2007, 06:18 AM
#2
Grey, it's not necessarily the ECU that's causing your grief, but the NATS receiver/controller/transponder unit. I'm not sure of the exact name, but there is a TSB on this issue that recommends replacing this unit when this problem occurs. That said, I don't know if the 98 ECU will circumvent this or not. The NATS device may continue to search for the key chip even with the 98 ECU.
Don't forget that the control for EGR system is entirely different from 98 to 99, but that may not concern you.
Don't forget that the control for EGR system is entirely different from 98 to 99, but that may not concern you.
11-15-2007, 06:33 AM
#3
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Grey, it's not necessarily the ECU that's causing your grief, but the NATS receiver/controller/transponder unit. I'm not sure of the exact name, but there is a TSB on this issue that recommends replacing this unit when this problem occurs. That said, I don't know if the 98 ECU will circumvent this or not. The NATS device may continue to search for the key chip even with the 98 ECU.
Don't forget that the control for EGR system is entirely different from 98 to 99, but that may not concern you.
Don't forget that the control for EGR system is entirely different from 98 to 99, but that may not concern you.
Thank you.
11-15-2007, 02:03 PM
#5
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I don't know that you can do that - in the EL section there is one wire shown directly connected from the NATS to the ECU - the rest is power and antenna connections. I suspect the wire (ecu pin 17) is a data connection that confirms the key when it's used, but ??????????
Anyway, we're going to trailer to the doctor's office tomorrow - they don't make house calls - I asked, and the local dealer owes me - the tech says that they have to plug into their Nissan computer to set the Consult, then they can re-program my car. Sounds bogus to me....
Anyway, we're going to trailer to the doctor's office tomorrow - they don't make house calls - I asked, and the local dealer owes me - the tech says that they have to plug into their Nissan computer to set the Consult, then they can re-program my car. Sounds bogus to me....
Last edited by grey99max; 11-15-2007 at 02:07 PM.
11-16-2007, 04:05 PM
#7
The waveform sent from the NATS IMMU to the ECU is complex (that's the only way it can make the signals unique for every unique key). It is not a simple voltage and or wave that can be easily replicated. To completely rid yourself of the system you must swap in a 98 (or earlier) ECU. I'll look into the FSM later to see wires need to be swapped around, if any.
Last edited by nismology; 11-16-2007 at 05:28 PM.
11-16-2007, 08:11 PM
#8
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NATS fixed today..
I took off work today, got the trailer out of storage, winched the max up on the trailer, then after lunch towed over to the dealer, waited around 2 1/2 hours and got the NATS thingie reprogrammed and working with both keys in 15 minutes, for $46....
Got some WOWs from the dealership staff about the 3.5 under the hood, but no grief about the engine swap causing the problem. I guess buying eight cars from them in 15 years means a little bit...
Got some WOWs from the dealership staff about the 3.5 under the hood, but no grief about the engine swap causing the problem. I guess buying eight cars from them in 15 years means a little bit...
11-16-2007, 08:13 PM
#9
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The waveform sent from the NATS IMMU to the ECU is complex (that's the only way it can make the signals unique for every unique key). It is not a simple voltage and or wave that can be easily replicated. To completely rid yourself of the system you must swap in a 98 (or earlier) ECU. I'll look into the FSM later to see wires need to be swapped around, if any.
Post #2 above mentioned differences in the EGR.... ????
Last edited by grey99max; 11-16-2007 at 08:16 PM.
11-16-2007, 09:43 PM
#10
Yeah, you know how the 99 EGR is a stepper motor design, where the 98 has the BPT valve and vacuum diaphram to actuate it.
They will not interchange. 98 ECU has absolutely no way to control the 99 stepper motor design.
They will not interchange. 98 ECU has absolutely no way to control the 99 stepper motor design.
11-16-2007, 09:53 PM
#11
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Also, unless you are controlling your auto transmission manually, you will need to swap in a 98 or earlier tcm if you are going with a 98 ecm.
Starting with the 99 model year, Nissan used a LAN style communication between the ecm and tcm. There are only 2 wires connecting the two. 98 and prior years had around 7 connections.
Starting with the 99 model year, Nissan used a LAN style communication between the ecm and tcm. There are only 2 wires connecting the two. 98 and prior years had around 7 connections.
11-17-2007, 08:44 AM
#12
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Also, unless you are controlling your auto transmission manually, you will need to swap in a 98 or earlier tcm if you are going with a 98 ecm.
Starting with the 99 model year, Nissan used a LAN style communication between the ecm and tcm. There are only 2 wires connecting the two. 98 and prior years had around 7 connections.
Starting with the 99 model year, Nissan used a LAN style communication between the ecm and tcm. There are only 2 wires connecting the two. 98 and prior years had around 7 connections.
Dang! It sounds like the '99 ECU still owns me..... I did find a Consult on eBay for only $7,500, but that's kinda steep prices for an occasional NAT fix.
Thanks for the feedback, guys. At least I have a trailer...
11-19-2007, 03:04 PM
#13
Haha the consults are expensive. We have 2 at my work, im trying to convince the service manager to sell it to me for 250$ and claim it was stolen 
damn it would be nice to have a consult-2 lol.
damn it would be nice to have a consult-2 lol.
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