2014 QX70S 5.0 Electrical problems

A

AlanD

Member
Car
QX70S
Just before the end of last year, I noticed the AFS warning light flashing a couple of minutes after driving off on a short local trip. Then the TPMS light came on too, also flashing. I continued to my destination and turned off the engine for a few minutes.

When I restarted the car the two lights were still there and the satnav screen said 'Please wait' for 3 or 4 minutes then 'SECURE' on a green rectangle. Nothing else on the centre console seemed to work; no radio/cd, heating controls etc. Heat/ a/c seems to still work but on the setting it was on when turned off.

I immediately checked the tyres but all were at 33psi.

Shortly thereafter the AFS light stopped coming on at all but TPMS always solid.

Since then I've driven about 500 miles and found that if you just hit the start button first without your foot on the brake and wait a few seconds then the satnav screen initialises properly and you can then put your foot on the brake and hit the button again to start the engine. Then the radio and satnav work for that journey. Nothing much else works on the centre console but the car drives and stops as normal. I'm not sure the Adaptive Front Lighting System is working though so that may be part of the problem.

Infiniti are no longer trading in Europe/UK so i took it to my independent (honda specialist) to check the codes.

There were quite a few and all seemed to point to a Body Control Module (BCM) issue so i bought a NOS item on e-bay and they fitted it and had it resync'd to the keys. Unfortunately, that made no difference to the problem.

There are a few Nissan dealers designated as Infiniti service specialists but my preference would be to go to an independent first and see if they can diagnose. One I have contacted said it would help if I could find service manuals/wiring diagrams online (even LHD).

Does anyone on here have anything they could share?

Google found
Infiniti QX70 (S51) - Service Manual, Repair Manual
but does anyone know if they are legit or a scam to get $10.

I will upload photos of the error codes later in case that helps anyone advise.
 
DSC_0034.jpg DSC_0035.JPG DSC_0036.jpg DSC_0037.jpg DSC_0038.jpg

If your clear the codes, they just come back as soon as the car is started.
 
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Alan,

I had a different but very obscure electrical fault a few years back. I went to a local garage that I have used before who are very good auto electricians but they couldn't solve the issue.

I decided to take to Westway in Coventry who are authorised Infiniti service approved. They had access to infinity technical support line who managed to diagnose the issue ...they had the car for 4 days as the fault only showed up doing a cold start so once the engine had been ran they had to wait overnight before doing another test.

Looking at your fault I would suspect the volts are dropping as you start your motor and boot the relevant on board systems at the same time. By letting the systems start first and the subsequntly start the engine those systems booted up might ride through the voltage dip....armchair diagnosis but I'd go looking at the battery or the battery connections to earth...maybe worth changing the battery?

Pete
 
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Thanks Pete,

I'll give that a try.

We did notice the diagnostic tester only reading 11.6V as shown in the pics.

The OEM battery failed just under two years ago and the replacement Varta N72 is an EFB type suitable for stop-start vehicles. I couldn't get the exact OEM replacement and the car had always seemed to struggle to turn over in cold weather since i bought it five years ago now, as did another one I tested but didn't buy at Infiniti Reading so I got the most powerful one i could get that would fit the battery compartment. It has 72Ah and CCA 760 and still cranks well enough but maybe it's down on volts for some reason ... or the ECU isn't regulating it properly.

I hope it's just the battery and not the alternator or the ECU...It's been fine for two years but maybe now isn't delivering the right voltage.

I'm in Surrey so if that doesn't work I'll maybe book it in with Ancaster in Slough so they can get access to the technical assistance line to help diagnose it. Another QX70 said they fixed an issue he had efficiently and they are bit closer to me.

Alan
 
Alan,

I'd try cleaning every earth connection before changing the battery...including the battery terminals. Perhaps also worth looking at all the relay and fuses to make sure there isn't corrosion on the blades.

I've no ideas where the earth's are so perhaps someone else can advise.

I am pretty sure it won't be the alternator as eventually the battery would drain and it wouldn't crank the engine.

One of the issues my local autotechnician was getting the latest diagnostic firmware for his tester..when he hit the reset every light on dash lit or flashed....although the car drove perfectly...the Nissan guys hit the reset and we were left with one one original fault....that they fixed.

One thing that might point to battery is if the symptoms started at the same time we had that cold snap at the start of December...got down to -8c here ....

Regards,

Pete
 
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I checked all the connections i can see and they all seem clean ans tight.

But I also took some readings with a multimeter and they're not great
11.98 initial resting
11.58 after 2 mins with lights on
8.36 cranking
14.58 running

so maybe a new battery is worth a try...
 
Alan,

Certainly looks like it might be the battery as it lost .4 volt in 2 mins ...the lights would pull about 10 amps and it you add another 5 for computers etc on the car that makes 15A so with a 72 Ah battery that is supposed to be more than 4 hours...and the trajectory (if linear) you are observed looks more like a 15 Ah battery as it looks like the voltage would expire after about an hour.

The 14.58 shows the alternator is charging.

With the numerous electrical gremlins you have I'd always look for a simple common denominator.

As you've already changed the common electronic unit to all systems...the bcm...it seems sensible to me to take a punt at the battery.

I looked at batteries on RAC website and they say it needs specialist install which makes me think perhaps some of the electronics loose their settings through a power down or something else needing dealer wizardry so I hope you don't find yourself in a load more trouble trying to do it yourself.

I'm not a car expert / professional but in your situation I'd be changing the battery.

After that I'd definitely be looking for a professional diagnosis.

Good luck and please keep posted on result!

Pete
 
Bumping this thread as I have a 2014 5.0 and experiencing the same charging issues at 130k miles. Car currently dead sitting in a parking lot after stranding my wife after work for the nth time. Will not respond to remote fob and the fob that came with the car when we bought it used years ago has a key that doesn’t match the car! Can’t get in. Will go back to break in to jump it, but after researching tonight, I’ve found that Infinitis use a “smart charging” system that is controlled by the BCM/IPDM. This supplies voltage to the battery as needed instead of constantly and tends to fail as the cars get older. I’ve been having small gremlins in the last 20k miles and have gone through several batteries…this stupid system is probably the root cause of it all. It’s a constant problem with the QX80 folks and all they have to do is cut a red wire to revert back to standard alt charging of the battery. Different wire for the sedans so likely different wire for FX/QX70. I can’t find any info online. I’m told the dealer does this procedure regularly, so I’m going there this week to check and see if they can do this and will report back. Between this and my need to disable the steering lock, which also causes a no start situation, maybe these gremlins can be exterminated. Stay tuned

Edit: apparently it was the starter that was bad with a malfunctioning rectifier/solenoid.
 
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there should be plenty of sites and forums that offer service manuals without having to pay.
 
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Jim165 said:
Bumping this thread as I have a 2014 5.0 and experiencing the same charging issues at 130k miles. Car currently dead sitting in a parking lot after stranding my wife after work for the nth time. Will not respond to remote fob and the fob that came with the car when we bought it used years ago has a key that doesn’t match the car! Can’t get in. Will go back to break in to jump it, but after researching tonight, I’ve found that Infinitis use a “smart charging” system that is controlled by the BCM/IPDM. This supplies voltage to the battery as needed instead of constantly and tends to fail as the cars get older. I’ve been having small gremlins in the last 20k miles and have gone through several batteries…this stupid system is probably the root cause of it all. It’s a constant problem with the QX80 folks and all they have to do is cut a red wire to revert back to standard alt charging of the battery. Different wire for the sedans so likely different wire for FX/QX70. I can’t find any info online. I’m told the dealer does this procedure regularly, so I’m going there this week to check and see if they can do this and will report back. Between this and my need to disable the steering lock, which also causes a no start situation, maybe these gremlins can be exterminated. Stay tuned

Edit: apparently it was the starter that was bad with a malfunctioning rectifier/solenoid.
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I don't suppose you've found any information on the smart charging facility? I've a constant 1.1A draw when the car is off and I don't think the battery is charging during normal operation (alternator supplying >14v). It's already killed one new AGM battery (Lion096AGM, 70Ah, 760cca) this year and I have to disconnect the battery when I park up.
 
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Bombtrack_77 said:
I don't suppose you've found any information on the smart charging facility? I've a constant 1.1A draw when the car is off and I don't think the battery is charging during normal operation (alternator supplying >14v). It's already killed one new AGM battery (Lion096AGM, 70Ah, 760cca) this year and I have to disconnect the battery when I park up.
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When I questioned the dealership’s tech that worked on our car about this system, he said he wasn’t aware of this model having the smart charging system. He said all of my drain issues were due to the starter wearing/shorting out. Since I’ve had starter replaced, zero issues as of this posting. If you haven’t had your starter replaced yet, it’s probably due if you’re experiencing dead batteries and charging issues. Like the radiator, it’s one of the mandatory items you’ll eventually have to replace at around 120k miles. Had issues like yours for nearly a year and the starter didn’t remotely have any symptoms of going bad like slow starts or skipping.
 
Jim165 said:
When I questioned the dealership’s tech that worked on our car about this system, he said he wasn’t aware of this model having the smart charging system. He said all of my drain issues were due to the starter wearing/shorting out. Since I’ve had starter replaced, zero issues as of this posting. If you haven’t had your starter replaced yet, it’s probably due if you’re experiencing dead batteries and charging issues. Like the radiator, it’s one of the mandatory items you’ll eventually have to replace at around 120k miles. Had issues like yours for nearly a year and the starter didn’t remotely have any symptoms of going bad like slow starts or skipping.
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I'm only at 55K miles on my 2014 so if there's no smart charging system then maybe the starter is the place to look next. Even on Amayama the starter is £500! I might see if I can crack it open to see if it can be fixed.
 
Bombtrack_77 said:
I'm only at 55K miles on my 2014 so if there's no smart charging system then maybe the starter is the place to look next. Even on Amayama the starter is £500! I might see if I can crack it open to see if it can be fixed.
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Yes, my starter cost about $800 from the dealership with $1000 labor for install. Mind you, that was a couple weeks after paying $2000 for new cooling fans and controllers. I hear there are some issues with the sunroof drain leaking into electronics, so that could be something to research. But yes, there’s a high chance that the starter is the root cause of your drainage. Dealer tech said the some electrical components within will short out and cause a draw.
 
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