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.
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Buick Rendezvous P0729 and P0723 Transmission Codes
Service engine light code said emissions problem. Replaced recommended part. A
few days later light back on although care drove ok. Now service traction system
light is on and brake pedal acts funny. Are these two problems related? What can i
do to fix this?
Comments
OK, so what are the codes and what part was replaced?
The traction and ABS brakes function together.