Buick Rendezvous help (come on, its a GMT still!)

TollKeeper

Original poster
Supporting Donor
Member
Dec 3, 2011
8,047
Brighton, CO
So ever since I purchased this vehicle, I have been having this random "Dash Reset". Theres no rhyme or reason to when or if it happens, it could be daily, or weekly. It does it once during the drive cycle, and wont do it again until the next day, or maybe week. The dash, and all accessories, headlights, tail lights, etc, turn off for a split second, and then back on. The engine and transmission are NOT affected. When I pull codes, I get none. But I had my emissions done recently, and it showed a loss of communication with CANBUS or something to that effect. It didn't affect me passing the emissions, so really didn't think anything of it, and it was the first time driving the car since I had bought it, so I didn't even think that it was relevant.

On the recommendation of another member here on the forums, I replaced the ignition switch over the weekend. And up until yesterday, that worked, until it didn't... I have read on other forums about people having similar issues, and hard wiring a connector under the throttle body fixed it for them. I don't have this connector as I have a rarer engine with the 3.6 High Feature. Wiring harness is on the other side of the engine bay, and is a completely different wiring harness. The other people that had this engine had the extremely more common 3400. On another forum I was reading that they had to redo the ground for the Tail Gate Module. But I will be damned if I can find the thing.

I will admit, I know very little about this truck. Although its the twin to my other car, My Wives Aztek, I have only ever had to do a tune up and oil change on it. And have not had to do anything more than an oil change and the ignition switch on the Rendezvous up to this point. I do have a NAV radio I am planning on putting in, but I wanted to get this dash reset sorted first.

Any help would be appreciated.
 

jmonica

Member
Apr 2, 2013
384
Hamburg, NJ
Uhg, these intermittent problems are the worst to track down. Anytime you can't recreate the problem it's a PITA to diagnose. The obvious answer from my viewpoint is a loose connector some place. I spent weeks trying to track down a similar problem on another car and it turned out to be that the relay wasn't pushed in all the way.
My guess is that nobody has ever had this problem which would account for the lack of replies.

Given that I'm not nearly as smart as the rest of the guys on this forum, I can only throw in what i would do which would be to start disconnecting and reconnecting anything related to the circuit with the problem. I am sure you can find the wiring diagram some place. Once again the problem is that unless there's an obvious disconnected connector some place, you may not know if you have fixed the problem until you drive it and see if it comes back on. Or work backwards and once you have the diagram, disconnect things until the problem is recreated, that gives you a starting point.

I'm really sorry that I can't be of more help man, good luck! Please post back if you do solve the riddle!
 

Maverick6587

Member
Dec 16, 2018
730
Sterling Heights, Michigan
If you're getting a CANBUS issue, try disconnecting the CANBUS connector and see if that fixes the issue.

Here's a link to a thread of mine where I had a CANBUS issue. I don't know if you acquired a Tech 2 or not but, Mooseman attached a video in his post. There are other troubleshooting steps in that video that helped me out A LOT, without touching the Tech 2!

After this weekend, I shouldn't "need" the Tech 2 for a few weeks. I could send it your way again if the basic troubleshooting doesn't help any.

 

TollKeeper

Original poster
Supporting Donor
Member
Dec 3, 2011
8,047
Brighton, CO
So I tore into the ABS light this evening, after finally getting a code for the left front wheel bearing.

Upon taking off the wheel, I found the wire harness off the bearing was rubbing on the CV axle, because the dealer had replaced the wheel bearing and routed the wiring incorrectly (dealer service before I owned it).

So now I have the wires routed correctly, and the wires are somewhat protected in whats left of the sheath. My question is, will the random ABS code I was getting for this wire shorting out on the CV axle possibly also be causing my U1301 CANBUS code?
 

TollKeeper

Original poster
Supporting Donor
Member
Dec 3, 2011
8,047
Brighton, CO
Another question regarding Air-Ride...

So my Air Compressor works, and the leveling system does exactly what its supposed to do. However, I wanted to inflate a basketball for my son, so I hooked up the extension hose, and adapter, and hit the button, but instead of air coming out of the air nozzle, my air suspension started going up. WTF?

So my next question is, what needs to happen to fix this?
 

Mounce

Member
Mar 29, 2014
13,667
Tuscaloosa, AL
Another question regarding Air-Ride...

So my Air Compressor works, and the leveling system does exactly what its supposed to do. However, I wanted to inflate a basketball for my son, so I hooked up the extension hose, and adapter, and hit the button, but instead of air coming out of the air nozzle, my air suspension started going up. WTF?

So my next question is, what needs to happen to fix this?
I would think a shuttle valve would move to output on the external hose. Maybe that valve is frozen/solenoid on the valve is bad.

I say this with complete ignorance to this system but that seems to explain why it had the adverse reaction instead of pressuring the hose.
 

Reprise

Lifetime VIP Donor
Supporting Donor
Member
Jul 22, 2015
2,724
So now I have the wires routed correctly, and the wires are somewhat protected in whats left of the sheath. My question is, will the random ABS code I was getting for this wire shorting out on the CV axle possibly also be causing my U1301 CANBUS code?


It might (I was originally going to guess 'no', given that that wire connects to the hub sensor... but it in turn, communicates with the ABS module, so I reconsidered) BTW, the description of U1301 is 'High Voltage on Class 2 Data Circuit'

According to a GM tech who posted this on another site (generic, not GM-specific), it's a bit of a bear to track down, and you pretty much have to catch it in the act w/ a scan tool running.

Since you've got access to the wire / connector you might try grounding it (3 sec minimum) and see if you can reproduce it -?

Here's some info... (given in response to an '01 HD pickup w/ the issue... no mention by the owner about ABS, but he did ask if it can result in loss of ignition). Words in boldface are as they were copied from the source (not my formatting). Obviously from a GM resource, but I don't know 'which one'.



CIRCUIT DESCRIPTION
Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. In addition to this, Node Alive messages are transmitted by each module on the class 2 serial data circuit about once every two seconds . When the module detects no messages and a high voltage on the Class 2 serial data link for approximately three seconds , U1301 is set and the setting of all other class 2 serial communication DTCs is inhibited.

CONDITIONS FOR RUNNING THE DTC

  • Voltage supplied to the module is in the normal operating voltage range.
  • The vehicle power mode requires serial data communication to occur.
CONDITIONS FOR SETTING THE DTC

  • No valid class 2 messages are detected on the class 2 serial data circuit.
  • The voltage level detected on the class 2 serial data circuit is high.
  • The above conditions are met for approximately 3 seconds .
ACTION TAKEN WHEN THE DTC SETS

  • The module inhibits the setting of all other class 2 DTCs.
  • The module uses default values for all parameters received on the class 2 serial data circuit.
CONDITIONS FOR CLEARING THE DTC

  • A current U1301 will clear when a valid class 2 message is detected on the class 2 serial data circuit or at the end of the current ignition cycle.
  • A history U1301 will clear upon receipt of a scan tool Clear DTCs command.
DIAGNOSTIC AIDS

  • This DTC cannot be retrieved with a current status. Diagnosis of a current U1301 is accomplished via the symptom, Scan Tool Does Not Communicate with a Class 2 Device. Refer to Scan Tool Does Not Communicate with Class 2 Device. See: Scan Tool Testing and Procedures
  • An intermittent condition is likely to be caused by a short to voltage on the class 2 serial data circuit. Use the Scan Tool Does Not Communicate with a Class 2 Device procedure in order to isolate an intermittent condition. Refer to Scan Tool Does Not Communicate with Class 2 Device. See: Scan Tool Testing and Procedures
 

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