No ABS but no lights or faults?
 

It was rainy today so I decided to see how well the ABS worked. It didn’t though LOL. All four wheels lock up, so I have that going for me. But I recently replaced the BCM and ECM, which recently allowed the vehicle to continue to run without issue. The only light I have is the check engine light for P0431 and 0421 which are bank 2 warm up efficiency faults. Now that you have the back story on the car for the most part, here’s what my issue is:

Now my question is, how come there’s no ABS light on and the ABS isn’t working? I used my scan tool (OBDMx+) and I don’t have any faults either Pcode or Manufacturer codes, I do hear however the grumble of a bad wheel bearing on the front left so I will be replacing that with a new one that I bought. But I would assume with the sensor is faulty it would still trigger light. The light does come on and then clear out when the car is started. Any ideas?

Does the abs light self check on startup? Maybe the bcm is from a Vue without abs. Do you have a traction control button on the dash? If so does it default to on, mine does. If you spin the tires on a gravel hill does it say low traction. My car does all this. If your vue is all wheel drive you may only abs without traction control. My daughter’s awd minivan only has abs without traction control.

I use the same scan tool for all the cars I work on.

It's may be a situation where the ECM and or BCM does not allow you to access ABS information with a standard OBD2 adapter running standard communication protocols. Obviously it is something that can be read with a Tech II at a GM dealership with whatever proprietary software they use to get at the manufacturer codes.

In general, you can't pull squat past very basic for an s series Saturn. Note that obdlink provides enhanced GM diagnostics but only for late model vehicles. And none of them are Saturn's.

Back then, 99% of Saturn things were Saturn only, including PCM's and BCMs. this is likely a case where you need a Saturn tool to pull from the manufacturer PIDs in question.

Is this a sudden issue that came to the forefront immediately after the BCM and PCM swap? If so I tend to agree it is probably a BCM issue and might be resolved by having a GM dealer flash your BCM to match your VIN and options. However, if it is a junkyard BCM they will likely refuse because it is not VIN matched to the vehicle. Their argument is that they have no way to verify the mileage of the vehicle which is stored in the BCM unless you took a photograph of the mileage before you swapped.

Whatled to you swapping both the PCM and the BCM? There might be a chance that one of them was not actually bad, and may allow you to put the original BCM back in for good. Or if for no other reason than diagnosis.

Its hard to say if there was a pre existing issue because the ABS light was on due to the faulty BCM that was replaced. The replacement BCM came from a vehicle that is equipped with ABS. But for all I know it is faulty as well, but the light is just not staying on. I'll check to see if I'm getting power to the ABS module and go from there I suppose. My OBD reader has the enhanced GM add on, but it still won't display the sensor information from wheel speed.

As I mentioned before, just because you have the enhanced GM diag on your reader does not mean your PCM supports display of that parameter via OBDII. Are you certain you have gone through all of the PID lists including the SAE pids?

Yeah the OBD LINK with the MX+ has "enhanced code reading" for the Saturn but not "enhanced diagnostics". I tried it on my wife's van and it reads and displays SOOOOO much more than the Saturn does. But I have abandoned the pursuit of ABS for the moment. I am tackling a leaky valve cover gasket that I just installed about two months ago 😒. I tried to use a gasket maker in conjunction with the new gaskets, because getting these things to seal up seems like an issue on the 3.0. But I am going to put a new set of Fel-pro gaskets in an do it dry so i don't have anything interfering with the gasket material. Thanks for chiming in though, I appreciate the advice.

Jordan

There is an Android app out there called car diagnostic pro. It's made by OBD scantech

The pro version will extract any code out of any vehicle including manufacturer codes for some of the vehicles. It has different libraries for the different brands of vehicles. It can't overcome a limitation of the vehicle not responding to a request for particular PID, but it will show you everything you can see short of a factory tool. You can even select sub modules and scan just them. The best $10 I ever spent on an app for my phone.

I'm pretty sure OBD scan tech did not write this program. They must have purchased it recently