Continuing starting issue for Nissan Frontier '03

Thread starter #41

Waddams

Senior Member
Waddams, I looked at wiring diagram for the starter and if your problem is that the starter won't crank over the engine, I don't see the problem being in the solenoid wiring inside the trans.
Am wondering about that myself. I've got the FSM's for the truck. I put a snip from the FSM power circuit diagram showing everything connected to that circuit. I think the "AT-MAIN" is what the mechanic diagnosed is shorting. That component, from what I can tell in the auto transmission and starter/charging system FSM also has the Transmission Control Module. Said TCM used to be called the Automatic Transmission Control Unit, or AT-CONT for short. Circuit 12 is labeled "AT-CONT" on the nameplate I pull off to get the J/B to replace the fuse that blew.

On several other Nissan forums, there are a bunch of stories of guys that the "AT-CONT" fuse keep blowing, and other issues, such as the relay that burned out on me before. Many times, they traced it back to a bad TCM shorting and pulling too many amps, blowing the fuse and/or burning out some element in the relay.

The fix was a trip to the dealer to replace the TCM and have the new one reprogrammed as it's a proprietary thing only Nissan can do.

Before you go the transmission route I suggest you find a qualified mechanic to pin point the fault instead of jumping to conclusions.
I understand the sentiment - the one that gave me this diagnosis performed an "advanced" electrical diagnosis test. Exact comments on the report are "found short in the transmission control harness located in the valve body of the transmission". I'm pretty sure the TCM is also wired in through the same wiring (but I'm not 100% certain).

I do appreciate that this mechanic basically told me that his fix was replace the transmission, but he thought I might be able to find someone that could fix it cheaper, so rather than try to hit me for that cost, he just replaced the fuse that was blown and advised to go check around to see who else I could find that might be able to fix it cheaper than full replacement. I thought the guy was being honest and reputable.

I do know that anti-theft security systems are a pain on older vehicles. I wish my 2001 4Runner didn't have one.
I don't believe it's equipped with a security or anti-theft system. The FSM's show where the relays, switches, dash lights, etc. should be for models that have it. In mine, the fuse box relay spaces are empty, the door switches are not there, the dash light spaces are just plastic covers with no lights.

If your truck has a security system there is a 10 amp fuse for the security relay that provides the ground for the park/neutral relay that provides power to that small wire on starter, if you do not have security then the park/neutral relay has a direct ground and the relay provides power to the small starter wire from 40 amp fuse for ignition switch. The neutral safety switch is powered from a 7.5 fuse. I don't mean to discredit the mechanic that diagnosed the problem but I don't see any connection between starter circuit and transmission solenoids. If you have a short blowing a fuse, then you know what circuit the problem is on and with some patience should be able to pin point the fault.
No security system per above. I agree with your point about the no connection above. If there is a connection, I think it's likely in the TCM going bad, through the AT-MAIN that runs off circuit 12 per the snip included.

As for the neutral safety system - mechanic said his tech checked the whole thing and did not find a short or any faults in the neutral safety circuits/switches/system.
There's a ton more diagrams in the FSM's for the starter/charging, transmission, and engine control system that all show portions. I haven't seen a diagram that puts it all together, and while I'm able to read electrical diagrams with a little knowledge, my skill level isn't up to this at the moment.

Given the N+P interlock relay blew, then fuse 12, both are tied to the NS system, but that system is also apparently connected to the TCM from what I can see, and yesterday's report, it seems most likely that the TCM is going bad, shorting, overdrawing, and the overdraw damaged the relay, then blew the fuse. That's my best guess at the moment.

I went ahead and snipped the AT-MAIN wiring diagram, showing the TCM connected through the AT-MAIN, which is what I think the tech yesterday called the transmission control harness. Also snipped the diagram from the AT FSM showing the PNP switch feeding to the TCM, via circuit 12, so I know the TCM is connected on circuit 12 to the neutral safety system.

I'm thinking my best bet might be a dealer who can replace and reprogram a new TCM, assuming dealer can confirm the diagnosis.
 

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Thread starter #42

Waddams

Senior Member
And one more - talked to a guy that I think I'm gonna take it to. Seemed very knowledgeable. Said since the 1st Gen transmissions aren't even made anymore, the remanufactured ones were so expensive, he actually had an aftermarket transmission from a Japanese import called JDM he could put in that would be an all new transmission, replace the wiring, TCM, valve body, - the whole shooting match, and since it was aftermarket import type stuff, it's cheaper. $2k +/- out the door.

If the radiator/transmission fluid cooling system needed replaced, he could do that too, or he could also do a flush job on the cooling system if it were still in decent shape for now.

He said depending on what he found, though, he might also be able to fix what was there. I think he called it "Consult II" - a diagnostic reader that would read all the transmission codes. Said most mechanics and dealers didn't have it anymore because it's older, and most don't work on the older vehicles like this. Said he had one and it would be a big help.

I know beware the free lunch and if it's too good to be true, it probably is, but I think I'm gonna at least take it to him and let him look it over. It's about 15 minutes from my house, I can work remote from home, so I'll probably drop it off for him, UBER home, and wait for the news.
 
And one more - talked to a guy that I think I'm gonna take it to. Seemed very knowledgeable. Said since the 1st Gen transmissions aren't even made anymore, the remanufactured ones were so expensive, he actually had an aftermarket transmission from a Japanese import called JDM he could put in that would be an all new transmission, replace the wiring, TCM, valve body, - the whole shooting match, and since it was aftermarket import type stuff, it's cheaper. $2k +/- out the door.

If the radiator/transmission fluid cooling system needed replaced, he could do that too, or he could also do a flush job on the cooling system if it were still in decent shape for now.

He said depending on what he found, though, he might also be able to fix what was there. I think he called it "Consult II" - a diagnostic reader that would read all the transmission codes. Said most mechanics and dealers didn't have it anymore because it's older, and most don't work on the older vehicles like this. Said he had one and it would be a big help.

I know beware the free lunch and if it's too good to be true, it probably is, but I think I'm gonna at least take it to him and let him look it over. It's about 15 minutes from my house, I can work remote from home, so I'll probably drop it off for him, UBER home, and wait for the news.
Some years/models had a recall on the radiator due to the ATF fluid getting contaminated. Maybe that's why he mentioned the radiator. Might be a good idea just to replace it. JDM engines are popular. I'm sure there transmissions are as well. Good luck!
 
First off ,, the radiators didn't have an issue with failing until 2004 when they went to a different transmission, so the guy that thinks that is tied in to the issue, doesn't know all he thinks he knows, second, on that unit the solenoid assembly inside the transmission is on a different circuit than the pnp switch, if there was an issue with the solenoid assembly you would have transmission codes and likely shifting issues,, so he's wrong there also,

This is NOT a complicated starting system, any "competent" mechanic should have no problem figuring this out,, and I stress the word " competent" ,

If I remember right this is a 2003 ? the transmission does NOT have a tcm inside the transmission, that started in 2004 with a 5spd automatic version of this unit, similar , but totally different unit. it sounds like some of the guys giving you advice don't know that ?

I'll send you my phone # over pm,, give me a call and I'll see if I can sort some of this out for you,
 
Thread starter #45

Waddams

Senior Member
i got your pm. thank you so much! my work day will be a real firedrill, not sure when I'll be able to follow up.

i will say i got the 03 because it was in the years without the ATF/radiator leak. figured it's easy enough to check for signs of contamination anyway, so did and this layman saw nothing concerning.

there was one guy with a local shop who sounded like he knew the details of differences btwn models. he sounded similar to you!

i am skeptical that the tech got this right. hence why I'm trying to learn more about it and find someone better!
 
Thread starter #46

Waddams

Senior Member
Took it to a guy that specializes in Nissans and Infiniti's. Not certain if a name/company drop is appropriate so I'll leave it off for now. I've also been on clubfrontier.org talking to people about this - the more knowledgeable posters input and this guy's all lined up. So - he ran several diagnostics, looked over the whole thing, I won't recount the details but will run down the summary that the truck is basically in need of an overhaul. The tranny, other stuff, it's 18 years old and has almost 200k miles on it. It's worn out, about to fail or not functioning well in some way. Not due to defect other than age and wear and tear. Basically, the components have done the job they were supposed to do for the service life they were supposed to do. They are:
  • Tranny - at idle, the line pressure is 0 psi. Hit the gas, it gets up to 91 psi. Proper spec is 94 psi. So there's a hydro leak in it.
  • Leak is causing tranny to run hot, might be causing wire damage of some nature that resulted in the short the prior technician's inspection found.
  • TCM might need to be replaced, it's plug and play if you can find one, so replace if can find one.
  • Air intake boot - broken and taped up to seal. He'd replace it (and I agree).
  • Bank 1 knock sensor not working.
  • Broken engine mount - motor raise up when you hit the gas. Might be contributing to stretching a wire somewhere, contributing to wire damage that's causing the no crank issue.
  • Other - while fixing, he'd flush the radiator, it's an aftermarket in good shape. No need to replace.
  • Rest of wiring all looked good to him.
  • As he works through it all, he'd also put everything he takes apart with new seals and gaskets.
  • Timing belt and water pump - belt didn't show any major defficiencies, was Nissan part, not cheap aftermarket. But no indication it's ever been replaced, same with water pump. Like is 18 years old and has almost 200k miles on it. I told him to price replacement into the work.
Other stuff, brakes, everything else - good to go. Looking at $3500-4000. He even has the right, brand new, never used, JCM tranny to use sitting in his shop, and they are apparently hard to get right now.

With the tranny problem, the truck as it is right now is on it's last legs. He said don't drive it long distance, try to stay off the interstate, take slow back roads everywhere you go.

He then said, do the work, the truck will be in like new tip-top perfect condition, good for 150-200k miles (assuming proper maintenance along the way).

So it's either a big chunk of money, or go find a new truck for a bigger chunk of money. I actually like the Frontiers, he talked about the timing belt and motor design being such that if the timing belt breaks, it doesn't damage the motor. Several other things that contributed to longevity. He did tell me if go get a new one, and it's a Frontier, the 16/17 models are the best value point right now. I guess they were the tail end of a prior generation of the truck? Had a bunch of features addressed that fixed earlier model problems before the next gen of them came out. He rattled off a bunch that I couldn't repeat, too quick and I'm not a car and truck guy to have taken it all in as fast it all came out.

I'll be surfing the web to look at trucks tonight.
 
I hate to rain on your parade, but the info he's told you about the trans isn't correct, not sure what pressure tap he checked, but it wasn't mainline pressure if it read 0 ?

Mainline should be minimum of 60-65psi, and should go up to around 120 to 140 in drive with throttle, with those numbers you posted if it really only had that much pressure you couldn't drive the truck ,,, it would be slipping its rear end off ! and low line does NOT cause one to run hot , sorry

Some of the other stuff he has said doesn't make sense either
 
Took it to a guy that specializes in Nissans and Infiniti's. Not certain if a name/company drop is appropriate so I'll leave it off for now. I've also been on clubfrontier.org talking to people about this - the more knowledgeable posters input and this guy's all lined up. So - he ran several diagnostics, looked over the whole thing, I won't recount the details but will run down the summary that the truck is basically in need of an overhaul. The tranny, other stuff, it's 18 years old and has almost 200k miles on it. It's worn out, about to fail or not functioning well in some way. Not due to defect other than age and wear and tear. Basically, the components have done the job they were supposed to do for the service life they were supposed to do. They are:
  • Tranny - at idle, the line pressure is 0 psi. Hit the gas, it gets up to 91 psi. Proper spec is 94 psi. So there's a hydro leak in it.
  • Leak is causing tranny to run hot, might be causing wire damage of some nature that resulted in the short the prior technician's inspection found.
  • TCM might need to be replaced, it's plug and play if you can find one, so replace if can find one.
  • Air intake boot - broken and taped up to seal. He'd replace it (and I agree).
  • Bank 1 knock sensor not working.
  • Broken engine mount - motor raise up when you hit the gas. Might be contributing to stretching a wire somewhere, contributing to wire damage that's causing the no crank issue.
  • Other - while fixing, he'd flush the radiator, it's an aftermarket in good shape. No need to replace.
  • Rest of wiring all looked good to him.
  • As he works through it all, he'd also put everything he takes apart with new seals and gaskets.
  • Timing belt and water pump - belt didn't show any major defficiencies, was Nissan part, not cheap aftermarket. But no indication it's ever been replaced, same with water pump. Like is 18 years old and has almost 200k miles on it. I told him to price replacement into the work.
Other stuff, brakes, everything else - good to go. Looking at $3500-4000. He even has the right, brand new, never used, JCM tranny to use sitting in his shop, and they are apparently hard to get right now.

With the tranny problem, the truck as it is right now is on it's last legs. He said don't drive it long distance, try to stay off the interstate, take slow back roads everywhere you go.

He then said, do the work, the truck will be in like new tip-top perfect condition, good for 150-200k miles (assuming proper maintenance along the way).

So it's either a big chunk of money, or go find a new truck for a bigger chunk of money. I actually like the Frontiers, he talked about the timing belt and motor design being such that if the timing belt breaks, it doesn't damage the motor. Several other things that contributed to longevity. He did tell me if go get a new one, and it's a Frontier, the 16/17 models are the best value point right now. I guess they were the tail end of a prior generation of the truck? Had a bunch of features addressed that fixed earlier model problems before the next gen of them came out. He rattled off a bunch that I couldn't repeat, too quick and I'm not a car and truck guy to have taken it all in as fast it all came out.

I'll be surfing the web to look at trucks tonight.
Yet after doing all that work, it will only be good for 150-200k miles? You are lucky on the timing belt not breaking.
 
Thread starter #50

Waddams

Senior Member
pressure was read while he had it a diagnostic box plugged into the socket behind the fuse box. he had one that couldn't connect, my truck threw a P0600 code, i thought it was comm link error related to transmission? I'd thought it was a tool to read the transmission, but it could not connect.

he plugged in another box, showed me the screen and gave me the printouts it produced. on the screen it was where I saw the 0 psi idle pressure and the 90 something psi pressure under throttle, and I have the print from that as well.

maybe I'm relaying info. wrong. probably likely.
 
pressure was read while he had it a diagnostic box plugged into the socket behind the fuse box. he had one that couldn't connect, my truck threw a P0600 code, i thought it was comm link error related to transmission? I'd thought it was a tool to read the transmission, but it could not connect.

he plugged in another box, showed me the screen and gave me the printouts it produced. on the screen it was where I saw the 0 psi idle pressure and the 90 something psi pressure under throttle, and I have the print from that as well.

maybe I'm relaying info. wrong. probably likely.
Printouts from any of the scanners look good for the customer, but actually have very little helpful information to them, other than listing codes, ( codes are simply the computers interpretation of what is happening, or not happening ) but most codes can have multiple causes, it doesn't show what caused the code,
it listing pressure for the trans is simply what the computer was expecting the transmission to have , that trans doesn't have a pressure sensor in it or on it,, it has no way of reporting to the tcm what the actual pressure is, the computer controls the amperage to the pressure control solenoid according to what it wants to happen, but if the solenoid isn't working correctly, or if there is an issue elsewhere in the hydraulic circuit, the computer won't know it unless there is a gear ratio error code thrown.

Hopefully the guy can sort it out for you, I get really aggravated when I hear of some shops feeding customers a line of bull hockey,,, trying to convince the customer they know what they are doing, it ends up being a reflection on all professional automotive techs, many don't care about their reputation, I do, this is my career , and has been over over 30yrs, if I wasn't honest with people I wouldn't have repeat customers, or a good reputation in my business, without a good reputation my job security wouldn't be very good ! it all ties together ,

besides, I try to live by that golden rule,,,
 
Printouts from any of the scanners look good for the customer, but actually have very little helpful information to them, other than listing codes, ( codes are simply the computers interpretation of what is happening, or not happening ) but most codes can have multiple causes, it doesn't show what caused the code,
it listing pressure for the trans is simply what the computer was expecting the transmission to have , that trans doesn't have a pressure sensor in it or on it,, it has no way of reporting to the tcm what the actual pressure is, the computer controls the amperage to the pressure control solenoid according to what it wants to happen, but if the solenoid isn't working correctly, or if there is an issue elsewhere in the hydraulic circuit, the computer won't know it unless there is a gear ratio error code thrown.

Hopefully the guy can sort it out for you, I get really aggravated when I hear of some shops feeding customers a line of bull hockey,,, trying to convince the customer they know what they are doing, it ends up being a reflection on all professional automotive techs, many don't care about their reputation, I do, this is my career , and has been over over 30yrs, if I wasn't honest with people I wouldn't have repeat customers, or a good reputation in my business, without a good reputation my job security wouldn't be very good ! it all ties together ,

besides, I try to live by that golden rule,,,
Would a mechanic have to have a gauge kit like this hooked up to the transmission to tell what those pressures actually are?
1631827691126.jpeg
 
Would a mechanic have to have a gauge kit like this hooked up to the transmission to tell what those pressures actually are?
View attachment 1104818
Yes, there are multiple pressure taps on a unit like that, you would hook up the gauges to the tap ports and check the pressures with it running in park and in gear, at idle and with your foot on the brake and other foot on the gas to check pressure at stall
 
Thread starter #54

Waddams

Senior Member
I understand and really appreciate your posts!

At the moment, I leaning towards trading the old one in on a new one. I like the Frontier's size wise. I end up driving into Atlanta for work sometimes, the smaller truck is easier to maneuver and fit into small parking spaces. I use mine to haul mulch in bulk once a year to my house to replenish mulched areas, the occasional stone run for slate chipped areas in the back yard. And then we got camping, I load it up for that.

Not to mention hunting trips. It's fine for me size wise.

Fix vs. trading on a newer one - am thinking even if this guy fixes all that was noted, it's an '03 with almost 200k miles on it. Ain't no telling how long what he doesn't fix will continue to last.

Been looking on autotrader, carmax, carvana - Carvana actually has prices a little cheaper, but the idea of buying without test driving (it's all online with them) just sits wrong. They do give a 30-day return policy, no questions asked. Suppose I could order, have it delivered, get it checked out, and return if needed. What a pain in the neck.
 
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