Expert help needed - VQ30 trans issues

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lockeed
Posts: 9
Joined: Mon Apr 09, 2012 7:52 am
Car: Maxima SE 2000

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Car is a Maxima SE 2000 with Aut. trans.

Symptoms: Car has erratic transmission operation. Car won't shift in 3rd and 4th gear. 4000rpm at 75km/h, if you push the o/d button and take it of, the transmission slips and engine rev to cutoff. Engine seams to work properly, and idle is good. Shifts from reverse, first to second gear is smooth. But will rev up or get back to first gear without behing needed or with any additionnal throttle.

What I've done so far:

-6 months ago:
Replaced the MAF sensor after an erratic throttle response episode - this was before the transmission problems started occuring. I also cleaned the throttle body at that time and replaced air filter.

-This weekend:
-I adjusted the TPS properly, to get 500ohms closed, and 4000ohms with WOT. Operation is smooth and gradual and you increase throttle.
-Took off the tranny oil pan, took off the solenoids and cleaned everything including the debris magnets at the bottom of the pan. Made the solenoids operate with current and made them "click" properly by cleaning them with compressed air. Tested - works fine. Reinstalled.
-Took out the TCM, opened it, checked for cracks, cold soldering issues and for fried components, board is perfect from the exterior, no issue. Reinstalled.
-Took a look at the crank position sensor under the engine, near the oil pan. Took harness off (was hard to get out), inside of the connector looks clean, no debris or grease. Didn't pull the sensor off tought...

I also did a scan, found the following codes:

-P0744 Torque Converter Clutch, Solenoid Circuit Intermittent
-P1446 Evap canister problem
-P0174 - too lean - bank 2 (I think this is normal as I have a small hole in the flexible part of the exhaust, just before the cat...)

I erased the codes after I had worked on the car, and went for a test drive. Car still did the exact same thing. Only the EVAp code came back (haven't check that yet).

What I suspect now:
-bad revolution sensor
-bad crack position sensor (don't know if it can affect the transmission operation like that tought...)
-TCM and/or ECM need a reflash / reprogram (considering I adjusted the TPS, changed MAF a while back etc...)

Let's hear what you guys think!

Thx


MaximA32
Posts: 635
Joined: Mon Jan 09, 2012 1:30 am
Car: '98 Maxima (RIP)
'04 Maxima - Traded
'06 Mazda 6S- Traded
'15 Altima
Location: Valley of the Sun

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I would say that you have a bad Convertor Clutch Solenoid judging from the code. You can find the diagnostic procedure here: http://www.nicoclub.com/FSM/maxima/2000/at.pdf

lockeed
Posts: 9
Joined: Mon Apr 09, 2012 7:52 am
Car: Maxima SE 2000

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I cleaned the Convertor Clutch Solenoid and made it work with 12V. It was "stiky" and hardly operated, but after cleaning it, it worked and clicked properly. I went to test drive the car and it did the exact same thing. It's very unlikely that it cause this by now...

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loystock
Moderator
Posts: 2144
Joined: Sun Sep 21, 2003 9:12 pm
Car: 10 Pilot, 97&03 Q45s, 97 I30 and 06 M35 Sports (04 G35 & 99 I30-RIP)
Location: San Jose, CA

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Check/replace the revolution sensor and associated cable.

lockeed
Posts: 9
Joined: Mon Apr 09, 2012 7:52 am
Car: Maxima SE 2000

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Trying to get the correct part, I see a lot of conflicting info on both the TCM and the revolution (speed) sensor.

Part #s seams to overlap on those revolution sensor at some point... Very hard to tell which one I need exactly... Some even refer to the tire size... stating that it fits only on 16" wheels... mine came with 17" standard...

On the TCM, there's a lot of different #s on the tags too... "M7" being the most common... there's also "MG"...

Any guidance would be apreciated.

Thx

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loystock
Moderator
Posts: 2144
Joined: Sun Sep 21, 2003 9:12 pm
Car: 10 Pilot, 97&03 Q45s, 97 I30 and 06 M35 Sports (04 G35 & 99 I30-RIP)
Location: San Jose, CA

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Do not confuse the Wheel Speed Sensor (for ABS) with Revolution Sensor (to TCM). The revolution sensor is mounted close to the top of the transmission and accessible by removing the driver side wheel well cover. Problem with this sensor may trigger a P0720 fault code or none at all. Please refer to the link below, especially page AT-134.

http://www.nicoclub.com/FSM/maxima/2000/at.pdf

Below is a link to Courtesy Nissan, revolution sensor:

http://www.courtesyparts.com/31935a-sen ... 49918.html

lockeed
Posts: 9
Joined: Mon Apr 09, 2012 7:52 am
Car: Maxima SE 2000

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I just brough the car back from the cotage tonight - so I just did 40 miles in 2nd gear!

Man I really tought I had found my problem tonight when I took off the splash guard behind the left front wheel, to get access to the revolution sensor on the tanny... There was a ground wire with a plug at the end hanging loos just beside the suspension. This wire was connected to a terminal under a bolt, on the side of the transmission housing. I put a new terminal on and re-installed it... Erased the code via OBDII, disconnected the battery for 30 minutes... then went for a test drive... same thing again... no 3rd gear...

Couple things I noted on the way back... Trans just don't want to get into 3rd. (and 4th off course...). When I'm in 2nd gear, if I take the O/D off, the transmission disengage and the engine revs... Putting it back ON locks 2nd gear properly again.

When going down hill, if I let the trans in D4, the rpm will just fall back to +/-1000RPM. If I take off the O/D then, there's a little bit of compression/decelaration from the engine which rev up a little...

One other thing, I checked the revolution sensor before bringing the car back tonight - there was some sort of oil on it and very small metal residue (like on the transmission pan magnets...). I cleaned it and reinstaled.

:gotme

lockeed
Posts: 9
Joined: Mon Apr 09, 2012 7:52 am
Car: Maxima SE 2000

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Tonight I took the complete valve body that was on the used transmission that I bought and installed it in the car. I also put in a new oil filter and swapped the rev sensor too while at it...

Transmission does the exact same thing as before :cry: :crazy:

Either the TCM is fried or it's a mecanical problem in the transmission...

The only thing I find weird is that the transmission still goes from 2nd to 1rst whitout any reason, as if it had no reference of speed or "power demand"... If it wasn't for that, I'd bet on a mecanical trans. problem...

lockeed
Posts: 9
Joined: Mon Apr 09, 2012 7:52 am
Car: Maxima SE 2000

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This morning, I was trying to find the cause of my low voltage... I cleaned both battery post and the terminals... Still voltage is in the high 11V range and now I have the battery sign lit up in the dash...

I'll try to get an output reading on the alternator tomorrow...

I also did a lot of tests on the TCM. All voltage or ohm reading seams to be within spec, expect one. The signal from the "Vehicule speed sensor" on pin #40.

This is what they say:

-Check voltage between TCM terminal 40 and ground while driving at 2 to 3 km/h (1 to 2 MPH) for 1 m (3 ft) or more.

-Voltage varies between less than 1V and more than 4.5V.


I tested mine and it jump all over the place. I get all sorts of readings ranging from 0 to 5V. (2.1V, 3.5V, 3.65V etc...). They say it should either be under 1V, or over 4.5V and mine doesn't do that... Even when the car is stopped, it still show 4.5 or 4.6 volts readings! (??)

Now when they say DTC VEHICLE SPEED SENSOR·MTR, what part are they reffering to? The transmission rev sensor, abs sensor, speed sensor in the speedo cluster ???

Again, thx for the help.

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loystock
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Posts: 2144
Joined: Sun Sep 21, 2003 9:12 pm
Car: 10 Pilot, 97&03 Q45s, 97 I30 and 06 M35 Sports (04 G35 & 99 I30-RIP)
Location: San Jose, CA

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The Revolution Speed Sensor provides signal to the TCM while the Vehicle Speed Sensor is for the Speedometer-ECM. Better address your low-voltage problem. Crazy things do happen when the alternator is failing. With engine off, a fully charge battery must have 12.6 VDC or higher. The alternator charging voltage must be >13.8 VDC (spec is 1q4.1-14.7 VDC).


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