Both braking and steering are computer controlled, so perhaps an update to software could have changed things?

A note about computer controlled braking and steering. Computer controlled doesnt mean there is no mechanical link between the brake pedal and the brakes. It still works by hydraulics. The computer has the capability to pull some hydraulic pressure away and supplement with regen. So dont worry, if the computer fails you can still brake. Same with power steering, computer failing would just mean assist would go away, but the steering wheel is still mechanically linked to the rack.

 

You are starting to worry me, just took our Volt in today for the battery reinforcement upgrade. I don't think I've seen any post about your situation in the past. Good luck with that and let us know how it progresses. I'll re post if mine does anything like yours. Ray

 

I had no change in the power steering or brake behavior after the battery reinforcement.

 

Hello, fellow Volt-lovers!

Ever since I took my Volt in for the battery enhancement over Memorial Day weekend, I've noticed a couple odd problems, and I'm wondering if they are related (to each other and to the upgrade).

There's nothing done to the steering or brakes during the battery enhancement upgrade. The only module that is reprogrammed is the HPCM2 and it would have no connection to brakes or steering.

I suspect the roughness you feel turning might be struts, so take it to your dealer. Mention the brake feel issue as well so they at least look at it , but there's no reason for air to get in there due to the work performed during the battery enhancemen campagn. So you might want to compare the pedal feel to another Volt.

Both braking and steering are computer controlled, so perhaps an update to software could have changed things?
Computer controlled doesnt mean there is no mechanical link between the brake pedal and the brakes. It still works by hydraulics. The computer has the capability to pull some hydraulic pressure away and supplement with regen. So dont worry, if the computer fails you can still brake.

Actually this is not totally correct. The Volt IS a brake by wire system and under normal operation there is no direct relationship between brake pedal apply pressure and brake circuit apply pressure. The driver is merely connected hydraulically to a pedal feel simulation.The pedal pressure created is an input and combined with pedal travel forms the establishment of the driver's braking intention for the software and IT then commands apply pressures to the front and rear caliper apply circuits.(and sourced from a high pressure accumulator within the brake pressure modulator valve -BPMV)
Yes, if there is an electrical failure, there will still be base brakes (called 4-wheel push through mode) but this is more due to a fail-safe electrical behavior inside the BPMV.

WopOnTour

 

There's nothing done to the steering or brakes during the battery enhancement upgrade. The only module that is reprogrammed is the HPCM2 and it would have no connection to brakes or steering.

I suspect the roughness you feel turning might be struts, so take it to your dealer. Mention the brake feel issue as well so they at least look at it , but there's no reason for air to get in there due to the work performed during the battery enhancemen campagn. So you might want to compare the pedal feel to another Volt.



Actually this is not totally correct. The Volt IS a brake by wire system and under normal operation there is no direct relationship between brake pedal apply pressure and brake circuit apply pressure. The driver is merely connected hydraulically to a pedal feel simulation.The pedal pressure created is an input and combined with pedal travel forms the establishment of the driver's braking intention for the software and IT then commands apply pressures to the front and rear caliper apply circuits.(and sourced from a high pressure accumulator within the brake pressure modulator valve -BPMV)
Yes, if there is an electrical failure, there will still be base brakes (called 4-wheel push through mode) but this is more due to a fail-safe electrical behavior inside the BPMV.

WopOnTour

Good info, but to be 100% clear, since we are talking about a sensitive topic, any electrical failure, or total electrical failure, will not result in a loss of braking. The solenoids, when they lose power, configure themselves in a way that allows for bypassing the simulator and applying the multiplied force of your foot directly to the brake pads at the wheels.

 

Never had a steering issue, but I occasionally feel and hear a somewhat abrupt change in braking at low speeds. How much I feel it seems to depend on braking pressure, incline, and weather...maybe phase of the moon too. It's subtle but inconsistent.

 

We just had the battery upgrade done, no changes other than the front turn signals don't work anymore.

 

Don't see any relationship between the turn signals and the battery enhancment campaign.
Was there anything else addressed on the same repair order? or JUST the customer satisfaction campaign?

So your front signals dont work at all? But the rears do? What about on the outside mirrors?

WOT

 

Could there be a relationship between TPMS (Tire Pressure Monitoring Sensors) and the battery upgrade? The first time I drove above 45 MPH after the upgrade, the LR and RF TPMS both started to intermittently lose contact (LR more often). It's also happened to be the first really hot days in Chicago. Do they remove the tires to do the upgrade and they didn't reset the TPMS?

 

Thanks for all the insight.

I'm a little dismayed to be the first one, but I will report back once I have the dealer check it out.

If there was no modification to the relevant hydraulics or electrical system, I wonder if any part of the front linkage could interfere with one of the forward reinforcement structures (assuming it wasn't installed quite right). I tried unsuccessfully to find good photos of the battery reinforcement itself.

Anyway, I will specifically inquire about the struts (known issue) and then treat the brake pedal feel changes as a potentially separate issue. Thanks again.

 

For what it's worth, I can address the steering issue.
When I first received my Volt, it was delivered by the salesperson to my house. When I first drove it, I noticed what felt like a "catch" when turning left and right to about 90 degrees. I was about to take it back to the dealer, but tried something simple: I adjusted the steering wheel position. It had been placed in the lowest position, and when I moved it to a higher position, the "catch" was gone.

I'm not sure if you're problem is the same, but it's worth trying.

 

You know what, I did lower the steering wheel not that long ago... Thanks for the input, I will investigate this!