Transmission Problems on my 2005 Buick Rendezvous
AWD light on.
GM Computer codes P0729,P0723. Checked all
connections to sensors in wheels and transmission. Fluid
has been changed as recently as 5k prior to problem. No
repairs just troubleshooting, had codes cleared, problem
re-appeared.

2005 AWD Buick Rendezvous 3.6Lt, Speedometer erratic,
lurching  acceleration and shifting at moderate speeds
around 35 to 50 MPH, AWD illuminates  and goes off
unable to set cruise control odometer reads error.  Had
codes cleared problem re-appeared, checked wiring to
PCM ohm checked wiring harnesses from wheel bearings
and from sensor in transmission all OK.

Can the sensor in the trans be accessed by the pan?  Is
this a common problem with  the
Buick transmission?  
Should I first replace the harness to the PCM?  Last  
question if it has to be fixed in the transmission can a DIY
selfer pull the trans, I'm a  very good mechanic.

Answer:
My charts are not showing a P0729 for a 2005 AWD.
No, this not a common problem. Have not really had this
too often.
Was wondering why you say checked harness from sensor
to PCM. My chart shows vehicle speed sensor wiring goes
straight to Trans control Module (TCM). Sensor is on tail /
extension housing of trans. Yellow and Purple wires.

Reply:
Sorry 0729 is one of the codes that reads output speed
sensor low voltage, and your right again it's the TCM
module located adjacent the air filter box. What about the
sensors in the transmission itself, can they be accessed by
the pan?

The  vehicle speed sensor and output speed sensor are on
and the same. See pic attached.
Look very closely at the wires at the sensor connector. Pull
on each wire to see is the  colored insulation stretches. If it
does, then the copper is broken inside the insulation.

Also, you can remove the sensor, use a mirror to get a
small screwdriver on the reluctor wheel in the trans. See if
the reluctor moves / spins. If it does, then the wheel is
broken. Other that, i would say just a sensor problem. This
would obviously affect  speedometer, cruise, dash cluster.

Visitor:
Ok fabulous,  So the sensor depicted in the picture is
removable as shown.  If the relucter wheel isn't broken and
the wiring is good the sensor can be replaced without  
removing the transmission. Your advice is terrific.

Yep, you got it. This is your most likely cause.


Buick Rendezvous 2003 Just purchased it -- used.

Question = the traction light keeps coming on and the
brakes feel like their come up through the floor. It's getting
worse.  Is this unsafe and who can I go to get it fixed?  I
need an answer asap as I'm going out of town tomorrow.  
thanks.

Answer:
You've most likely got a bad wheel speed sensor, that is
part of the
anti lock brake system. When these go bad, the
symptoms are usually the traction light or ABS light coming
on, and an odd feeling in the brake pedal as you come to a
stop.

You would need to get the vehicle scanned to see which
wheel speed sensor is acting up, as it would have set a
code. The sensors are part of the hub bearing assemblies
for each wheel. Which ever one is acting up, you'll need
that particular hub replaced. That should solve your
problem.
Buick Rendezvous P0729 and P0723 Trans Codes
Comments
OK, so what are the codes and what part was replaced?
The traction and ABS brakes function together.

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Service engine light code said emissions problem. Replaced recommended
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