My 2002 Maxima spontaneously goes into what I believe is limp mode. Usually the ABS light comes on, I can't accelerate past 5 mph. I have to come to a stop the turn off the car then back on. It's not consistent. I saw other posts that said this was likely the alternator. It seemed like it could be as the battery also just went toast. But I got an alternator tester (clip onto battery style) and it says alternator is good. There is no check engine light on but when I scanned it pulled several codes:

P0732 - gear 2 incorrect ratio
P0733 - gear 3 incorrect ratio
P0328 - knock sensor 1 / high bank 1

Where would you start to determine the best way to solve this?

I just want to get this solved easily as I was going to sell the car this summer anyway. But with this happening seems near worthless.

Any advice would be appreciated. Thanks

 

Describe your alternator test in excruciating detail , so I won't believe it's your alternator that's gone bad (voltage regulator to be exact).

Because I believe your alternator is bad.

 

hey @aackshun thanks for the response.

First I connected alternator/battery tester to the battery terminals. Revved engine to 2000 rpm. The indicator stated the alternator was good.
I now realize that perhaps I shouldn't have relied on a $7 amazon tool.

after your post I to tested with a multimeter and here is the test I performed.

Multimeter on Battery Terminals
Engine Idle - 14.21
With ac/headlights/stereo/flashers - 13.99 to 14.06
Rev to 3000 rpm - 14.55 to 14.99 occasionally to 15.33
Turn off engine - 12.96

I'm not sure if this method is right but... Multimeter on alternator positve and negative on battery
Car Off - 12.8
Engine On with ac/stereo/lights/flashers - 13.2 to 13.4

 

Yes, your method is good, that's what I would do.
And there is nothing wrong with your alternator.

Your car is telling you what's wrong: There are two codes (P0732, P0733) both related to your automatic transmission. To diagnose, download the AT section of the FSM (use the link in my signature below). Then, look up the trouble diagnosis for the two codes on pages AT-132 to AT-138. To make it short, your suspects are:

• Shift solenoid valve A and/or B
• Each clutch
• Hydraulic control circuit

I suspect you need a new solenoid. Or perhaps some cleaning (as the problem is intermittent).
I would ignore the third code until after you fix your transmission.

 

I'll look into the shift solenoid you mentioned. Would those codes throw the car into limp mode and have the abs/battery lights go on? The car seems to be driving fine then comes out of nowhere. it's happened when i've been going 50mph+ on the highway.

 

That's your problem. Replace your alternator.

Unless you're interested in rebuilding it, only the voltage regulator is shot.

Anytime your voltage gets that high the car will kill circuits for thier protection.

Mine slowly went bad it got to the point to where the regulator was stuck at idle so I couldn't go higher than 2krpm at all times because the voltage would spike...
and you'll get a barrage of random codes and things shutting off exactly like you describe.

 

I just checked and aackshun is right and I was wrong.
15.33V is indeed too much - I incorrectly assumed it's something like 16+V.

 

Thank you, both.

I ordered a remanufactured OEM alternator. I will report back. Hopefully that will correct the limp mode issue as that's the only one making this vehicle unreliable.


regarding PO732 and P0733, I did notice shifting is delayed into 2nd and 3rd so I believe those codes are separate from the alternator issue. I did change the transmission fluid and add LucasOil transmission treatment. I use my Maxima as a daily driver running errands so I'm rarely driving more than 35mph.

I've had this '02 for 13 years and this is the first reliability issue I've dealt with.

 

I had an alternator that went to 15+ volts and the drive by wire stopped working. No codes, car would start fine. Once you put it gear it would die. Replaced the alternator and all was good.

 

My OBD2 tester can test both the battery and electrical system...if yours doesn't get your battery base voltage, start engine and test alternator output at battery, then start turning on all the loaded circuits (Headlights, Foglights, A/c blower full speed, caution lights, & brake lights) if your car is still producing more than 13.0 volts the alternator is good!

 

what happens if you leave the car idling in the drive way for 30 minutes? mine was doing weird stuff here and there for second or 5 on the way to from and work. THEN i i jsut let it idle for like 45 minutes in the driveway and sure enough the dash was light up like a Christmas tree and the battery voltage with the car running was 12.5 volts. turns out HEAT is a factor with electronics.

EDIT: Friend's dodge had drive by wire go faulty. turns out the battery has loose short in it that would randomly cause voltage spikes and drops. unfortunately and fortunately for him, he managed to make it out the school zone before the car randomly went W.O.T. i'm sure in another 15 years there will be a class action.

EDIT: when my alt first went the car started randomly and delaying shifts on the highway, and was pretty much dead. THEN the dash light up.

 

picked up a remanufactured OEM alternator on ebay. it arrived today and I had it tested at autozone. it passed their test. So now i'll remove the old one and swap it in.

 

Good luck! It is not the easiest alternator to replace. I displaced the a/c compressor to change mine, but I have seen people remove the radiator to gain access.

 

well that was more frustrating of a repair than I had anticipated. But it's all back together now.

Alternator Test with refurbished oem (I had this alternator tested at Autozone before installing)

Positive on Alternator Terminal
Negative on Battery Negative Terminal.

1. Car On, Lights On, AC, Stereo, Flashers 13.88v

2. Car on Nothing else on - 13.94

3. Car Off, nothing on. 12.72

Battery Test (multimeter connected to battery positive and negative terminal)

1. Engine On, Stereo, Lights, Flashers - 13.66v

2. Engine On, Stereo, Lights, Flashers, Rev to 3000 RPM - 13.77v

3. Car Off, Nothing On - 12.72

Do this voltage in these tests seem right? Seems low to me.

In addition I did a voltage drop test.

Voltage Drop Test
Positive - .14 to .16 (revved 2000rpm)

Negative/Ground - .04 (revved 2000pm)

The voltage drop of .16 is within the ok range to my knowledge.


I drove the car around a few blocks and had no issues. I took the old alternator that I pulled out and it passed the Autozone Alternator test 4 times.

I'll drive around some more tomorrow to see if I get that issue again. Any input on the voltage from these tests I ran after installing?

 

It's OK, but it's clearly wearing out. I consider under 14 to be failing. 14.7 is spec even with some accessories on.
3000 rpm and it's not even at 14V...she's gonna take a dump sometime. It's just a straight used alternator. If it had a new VRM installed, then it wouldn't have **** voltages.

I would replace for peace of mind, b/c you won't get far on battery when VRM pops.

I'm still trucking on altys from Advance (carquest remans).

 

Idle

 

Thanks for posting that. I'll got double check the belt tension. perhaps it's not tight enough and therefore not generating full power.

no random limp mode so far though. so that's an improvement.

 

Update: I adjusted the drive belt so that it can turn just under 90 degrees when twisting it. Previously I could turn it past 90 degrees, so perhaps it was too loose for the alternator to generate full power.

I did the alternator test again and it got up to 14.24 at idle and with accessories on and at 2000 rpm it was at 14.00 to 14.08

Now I'll get back to driving it around and see if the limp mode returns.

So far I've replaced the battery and swapped out the alternator with a refurbished OEM alternator. Drive belt was fine.

As for the P0732 and P0733 codes (2nd and 3rd gear incorrect ratios). I changed transmission fluid and added a LucasOil trans fix additive. It needed to be done anyway. I cleared the codes though and will see if they return.

As others have suggested, the trans codes are unlikely to have been causing the limp mode issue. I'll post any updates.

Thanks for all the help.

 

Stuck in 3rd gear is another limp mode that the tranny will trigger, though (but, yeah, V was your problem before for sure).
Low V can cause all kinds of codes. If you didn't have any of that stuff until alternator **** the bed, then I'm sure that's what it is.

 

It's like magic! It;s less expensive if you check all the obvious free stuff don't you think Sir?