Continuing starting issue for Nissan Frontier '03

[Waddams]

and...development. it started fine...until evening. had my wife sit in it and crank it while I played with the multimeter. confirmed the starter was getting hit with 12.8v while she cranked it.

the negative battery connection had always had loosening issues so i hack sawed the connector off and put a new connector on that fit better after a shim piece didn't help. but that didn't make a difference in the starting issue unfortunately.

what did - after confirming starter was getting power, then i knew something was interrupting the start. i ended up taking off the "N+P/Clutch Interlock" relay, blew off contacts, put it back on, and the truck started right up after that.

so, the starting issue (i think) is that the neutral safety switch signal is not always getting relayed properly to let the starter crank. removing the relay, cleaning the contacts, and reinstalling let the truck start right up.

or the whole thing was a fluke. I'm gonna buy a new relay and put it on.

any thoughts on how to better clean the contacts in the fuse box socket it plugs into? I took a thin nail and scraped it around inside the socket holes to try to get anything on the contacts off. the relay contacts were shiny copper/brass, no carbon or corrosion build up on them.

 

[NE GA Pappy]

and...development. it started fine...until evening. had my wife sit in it and crank it while I played with the multimeter. confirmed the starter was getting hit with 12.8v while she cranked it.

the negative battery connection had always had loosening issues so i hack sawed the connector off and put a new connector on that fit better after a shim piece didn't help. but that didn't make a difference in the starting issue unfortunately.

what did - after confirming starter was getting power, then i knew something was interrupting the start. i ended up taking off the "N+P/Clutch Interlock" relay, blew off contacts, put it back on, and the truck started right up after that.

so, the starting issue (i think) is that the neutral safety switch signal is not always getting relayed properly to let the starter crank. removing the relay, cleaning the contacts, and reinstalling let the truck start right up.

or the whole thing was a fluke. I'm gonna buy a new relay and put it on.

any thoughts on how to better clean the contacts in the fuse box socket it plugs into? I took a thin nail and scraped it around inside the socket holes to try to get anything on the contacts off. the relay contacts were shiny copper/brass, no carbon or corrosion build up on them.

you could spray them out with a high quality contact cleaner.

also Napa Echlin makes a contact enhancer, CE1. It isn't cheap, but it is a great product, and can make a big difference in the resistance across a connection. It is used mostly on ECM connections, but will work anywhere there is a friction electrical connection

 

[NE GA Pappy]

is this a 3.3 6 cylinder?

 

[Waddams]

yes sir, it's the 3.3L 6 cyl engine.

have been reading more truck and Nissan forums. others over the years have reported a wild goose chase that ends with replacing this relay.

I'll definitely get the contact cleaner and enhancer to try out. I'm a bit excited, this is the first time I've had the no crank problem, then managed to do something specific that immediately after the truck started. If this turns out to be the issue, I'm gonna be one happy dude.

 

[NE GA Pappy]

when you said you tested for the 12.8VDC, what lead were you testing on the starter? You should have a constant voltage to the positive battery lead. It is the small diameter wire that you should be testing for voltage. If you have switched voltage on that small wire, you have a solenoid on the starter issue.

 

[Waddams]

voltage was constant on the positive battery cable, accessed under the truck where it is snugged onto the starter lug. zero on smaller wire from the ignition circuit when wife cranked. i had her crank multiple times so i could check both and get repeatable results.

I'm by no means an expert mechanic but I have an engineering degree (water supply and treatment) and have rudimentary understanding of electrical sparky things. I've been digging into the Nissan service manuals for my truck's ignition system trying to find the gremlin. It's not certain in my mind, but after much tinkering I've finally had success with getting it to start after a specific, singular action with the relay. I won't know for certain unless I can come back in 3 months and report no more issues, and I am also going to change out that relay.

At the moment, the truck has new starter/solonoid, new ignition switch, new spark plugs/cables/distributor cap/ignition coil, 3 of 6 injectors replaced, the wonky battery connector replaced, and all the general contact and connection checking/tightening/clean up I did to it. It still might be another problem buried in the system, I know when one part goes it tends to fry out more before you figure it out and get fixed.

Earlier today I actually did pull every other fuse and clean the contacts with a wire brush. All the blade fuses had significant black carbon build or corrosion build up on them. I scrubbed them clean with a pistol barrel wire brush. The larger amp fuse links didn't have that build up that I could see. I do wonder what's in the sockets that I can't get to.

I might spray contact cleaner in all of them just for good measure.

I'm hopeful that this relay thing will turn out to be it, but aware it might not be, or the relay might be on the way out as well as additional problems in the N/P system, or the crank shaft position sensor, or a control module is going bad, or other things I probably don't even know exist. s. I'm struggling thru one piece at a time and will until the no crank problem goes away, while hoping to not spend a mint in the process.

I'll have a good understanding of ignition systems by the time this is done, though.

 

[NE GA Pappy]

crankshaft position sensor will not cause a no start problem. The computer can't tell the sensor is bad unless the engine is turning over, so there is nothing in that circuit that will keep the engine from turning over. If you have constant voltage to the starter, but none on the small wire, then you have a start signal issue. You are on the right track with cleaning all the connections. There aren't many parts in that system. The ignition switch, the neutral/safety switch, the plug in solenoid, and some run it through the brake switch also. I would have to see a diagram on the truck to know that, and I haven't looked at one.

Is ANY other electrical stuff wonky on the truck? Intermittent light flashes, radio goofing up, a/c controls that don't work? Horn work all the time? anything at all?

 

[Waddams]

no light issues or anything, but the horn has never worked right. its always been a very weak honk. nothing intermittent until the no crank problem.

 

[transfixer]

no light issues or anything, but the horn has never worked right. its always been a very weak honk. nothing intermittent until the no crank problem.

I don't remember the original post on this, as far as what you've done already, but one thing I'd suggest is removing and cleaning all the ground connections on the wire harness, where they bolt to the engine or even frame, and by cleaning I mean with a wire brush or sandpaper and then re-tightening all grounds, your issue with the horn made me think of this,

also have you replaced the inhibitor switch ? ( glorified neutral safety switch on the side of the transmission )

 

[Waddams]

I don't remember the original post on this, as far as what you've done already, but one thing I'd suggest is removing and cleaning all the ground connections on the wire harness, where they bolt to the engine or even frame, and by cleaning I mean with a wire brush or sandpaper and then re-tightening all grounds, your issue with the horn made me think of this,

also have you replaced the inhibitor switch ? ( glorified neutral safety switch on the side of the transmission )

cleaning the grounds - wire connectors and the locations they attach - is on the agenda as well, my friend. just for good measure if nothing else.

i have not replaced that inhibitor switch. i have looked it up, know where's it at, know the cost to get the part, etc. it's got a heat shield over it and it's tucked up on top the transmission on my vehicle. it is a royal pain in the neck to access. at some point, i do want to take that shield off and clean up behind it. i can see where dirt and muck has gotten in there. i want to get that stuff out of there.

for going to work this morning - truck started fine, no issues. i went to autozone and bought a $20 replacement N+P interlock relay before going to work. according to a nissan car forum, the N+P interlock relay is basically the starter relay, but it also ties in the signal from the inhibitor switch? i think that's basically how the poster on that forum described it.

that's the part that i monkeyed with last night - it wouldn't start, i pulled that relay, cleaned contacts, put it back, and it started right up after. if the no crank happens again, i'm just gonna put the new one on and see what happens.

crankshaft position sensor will not cause a no start problem. The computer can't tell the sensor is bad unless the engine is turning over, so there is nothing in that circuit that will keep the engine from turning over. If you have constant voltage to the starter, but none on the small wire, then you have a start signal issue. You are on the right track with cleaning all the connections. There aren't many parts in that system. The ignition switch, the neutral/safety switch, the plug in solenoid, and some run it through the brake switch also. I would have to see a diagram on the truck to know that, and I haven't looked at one.

Is ANY other electrical stuff wonky on the truck? Intermittent light flashes, radio goofing up, a/c controls that don't work? Horn work all the time? anything at all?

The Nissan factory service manuals are all online, the link for the '03 Frontier starting system is here: https://www.nicoclub.com/service-manual?fsm=Frontier/2003/sc.pdf

I found the site for the manuals yesterday.

I'm cautiously optimistic that since I was able to get it start immediately after working on the N+P interlock relay that I may have figured out where this gremlin is and be on track to fixing it.

 

[transfixer]

cleaning the grounds - wire connectors and the locations they attach - is on the agenda as well, my friend. just for good measure if nothing else.

i have not replaced that inhibitor switch. i have looked it up, know where's it at, know the cost to get the part, etc. it's got a heat shield over it and it's tucked up on top the transmission on my vehicle. it is a royal pain in the neck to access. at some point, i do want to take that shield off and clean up behind it. i can see where dirt and muck has gotten in there. i want to get that stuff out of there.

The switch i'm talking about isn't on the top of the trans, only thing up there is an input speed sensor, the inhibitor switch, ( or PNP switch) is bolted to the passenger side of the trans right above the pan, should have one maybe two 8mm bolts holding it on, the wires that go into it run up to the top of the bellhousing/back of engine, and there will be two connectors right there , one will be for the switch, they can be kinda hard to reach, sometimes we get them from up top. That is what tells the system whether you're in Park or Neutral, and they do go bad.

 

[Waddams]

The switch i'm talking about isn't on the top of the trans, only thing up there is an input speed sensor, the inhibitor switch, ( or PNP switch) is bolted to the passenger side of the trans right above the pan, should have one maybe two 8mm bolts holding it on, the wires that go into it run up to the top of the bellhousing/back of engine, and there will be two connectors right there , one will be for the switch, they can be kinda hard to reach, sometimes we get them from up top. That is what tells the system whether you're in Park or Neutral, and they do go bad.

Yeah, we're talking about the same switch. I can't find a good pic on the 'net, and didn't take a photo of the plate that covers it when I was under there. I can peak through a space about 1/2-inch wide and see the switch when under it the plate I'm talking about though. Maybe getting that plate off opens it up and it's easier once that plate is off than I'm thinking.

I made sure to park where the truck would be in full sun at work this afternoon. Might be just a fluke that afternoon heat seems to contribute to causing the issue but we shall see.

 

[beretta]

This stuff is the cat's meow, but expensive-
Good stuff. Helps ensure good clean metal to metal contact.

 

[Waddams]

And one more update. Had to leave work early - get in truck, it had been sitting in the sun and was nice and hot. No crank, lights all on, same old thing. Put in the new N+P interlock relay - and it started right up.

So now I'm at the relay itself was going bad, something about the extra heat is keeping it from closing.

Or it's a "fix" that overcomes some other problem in the neutral park switch system and I haven't figured it all out yet. But if it isn't just the relay, then it's something in that part of the system.

Next step - see if new relay continues to have no crank problem. Fingers crossed.

 

[NE GA Pappy]

This stuff is the cat's meow, but expensive-
Good stuff. Helps ensure good clean metal to metal contact.

I bet that is the same stuff as the Echlin CE1. It comes with the little brushes, squeeze bottle and all just like that

 

[Waddams]

Autozone had their version of it. I just bought the little squeeze bottle and used the end of pen to apply it to the new relay contacts.

Edit - I took the old relay apart. It's got clear damage in it. Several of copper lines linking different parts are broken. Looks almost like a light bulb filaments that burned out. Not all of them, but some.

Looks like the contact is permanently closed to indicate it's not in park or neutral because of that broken line. Now I gotta worry about what caused it to break. Age? or did resistance in the circuit build up from something and cause it to overheat and burn out? I might buy a 2nd spare relay just in case!

 

[Waddams]

well that new relay fried out. no crank again. got a short, bad ground, or NPP switch issue. instead of at the lease for opening bow wknd, it's at a mechanic. at least it didn't die 2 hrs from home in the woods.

i might ask 'em if they can just rig a bypass around the neutral safe switch instead of hunt down whatever it is.

 

[Waddams]

Another update. It stopped working again. Same issue. No crank, no start. I took it to mechanic. Updated mechanic on issue, that I'd apparently solved it by replacing the N+P Interlock Relay. Then the relay apparently blew again.

So, mechanic went through diagnostics with the truck actually messing up so he could pinpoint the problem (which was a first, 3 prior attempts, truck would not misbehave so they couldn't figure it out). This time - tech has come back with good news/bad news. It's running again. Replaced relay and upsized a fuse from 10amp to 20 amp (he told me which, I don't remember exactly which one). Apparently, there is a wiring pack INTERIOR to the transmission that connects to the neutral safety system. That wiring pack has a short in it. The fix is not replacing the neutral safety switch or any of the wiring - he said they check it all, there's no issues with those. The fix, he says, is to find a replacement transmission that has a good wiring pack inside it and replace the truck's transmission.

He further said maybe there's a specialist that could break that transmission down, repair/replace the wiring pack, and fix it that way, but he didn't think that was a job his shop and his tech's would be able to accomplish reliably.

He also didn't know the cost to replace the transmission as he hadn't been able to find one yet from his suppliers. It will probably be a remanufactured or used one. I'm reasonably sure Nissan isn't making new ones for a 2003 anymore.

So either I pay to replace the transmission on a 2003 truck, or go looking for a new truck.

 

[DAVE]

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. Before you go the transmission route I suggest you find a qualified mechanic to pin point the fault instead of jumping to conclusions. 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.

 

[Artfuldodger]

Wow, that sounds expensive and might not even really be the problem. Does security systems prevent cranking or starting? I do know the neutral safety switch will prevent cranking. But your mechanic is saying the wire pack in the transmission is somehow a part of the Neutral Safety System?

Could you mount a momentary start switch and bypass the neutral safety system and that internal pack? You'd think there would be some hack to spice wires coming from that internal transmission wiring pack if that's what's keeping it from cranking.

I do know that anti-theft security systems are a pain on older vehicles. I wish my 2001 4Runner didn't have one.