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2003 Rendezvous cx problem

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Old 09-23-2014, 04:51 PM
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Default 2003 Rendezvous cx problem

I am having a starting problem. Most of the time it will fire on the first crank, sputter and die, the second crank it will start right up. Other times is will crank and crank with no fire, but if i spray a little carb cleaner in the intake it will fire up and run perfect. I have 50 psi fuel pressure, and the regulator has been replaced, and the fuel filter. I believe it to be a security problem as the light has come on a few times. I read the codes and here is what it gave.

BCM codes: U1016, U1040, B2961.

Powertrain codes: P1626, U1040, U1064, U1300.

I have done some searching and found the key switch is common and the bcm but i dont want the throw parts at it. I'm seeing if any one has experienced this at all? Thanks
Old 09-23-2014, 05:45 PM
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50 psi may not be enough to make it run. Some V6'* need about 43, some others 55+

But, you have 2 U codes thats saying the PCM can't talk to the BCM and the BCM can't talk to the PCM. Both of them are reporting this. So it seems like we have a bad link between the 2 modules. And probably the best way to test this is to get to a dealer that has a Tech2 diagnostic tool that can "talk" to every single module in the car.
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Old 09-24-2014, 10:37 AM
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I have a snap on scanner where I can see all live data of both modules, and turn off really anything I want to. Can tech 2 do more then this?
Old 09-24-2014, 07:23 PM
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Of course the Tech2 can do more. Its designed to be the highest diagnostic tool for GM vehicles. Its the only one that can reprogram GM modules, stereos, PCM'* BCM'*, etc etc.
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Old 09-24-2014, 10:25 PM
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If the vehicle cranks over, the PCM is getting a signal from the PassKey III module......thus it grounds the starter relay, and the fuel pump relay......I am not sure if the PCM receives the fuel enable signal from the PK3 moduel or the BCM....

The fact it starts, with a shot of carb cleaner, may mean the fuel pressure is borderline as Mike has suggested....maybe some one can look up the fuel pressure specs....

B2961 and P1626 have to do with the theft deterrent system......what you are going to have to do, is clear the codes and when the vehicle won't start, recheck to see which codes may have returned......comm codes are hard to diagnose, especially if intermittent....
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