2005HHRauto

Wheel hub ABS sensor question for ChevyMgr , or anyone , with
GM ABS wheel hub / sensor knowledge...:twothumbs

Help......

I'm in the process of switching over to 4x100 15x7 , Enkei RPF1s , on
my 2009 HHR SS .

RPF1's are 9.5lb , my Dunlop street tires are 20lb , 30lb total mounted, on the scale, w/ TPMS too..:twothumbs

Just mounted the rears, using Cobalt 4 lug ABS wheel hubs, off of ebay.
2 REAR Chevrolet Pontiac Saturn 2003-2009 WHEEL HUB AND BEARING ABS 4 LUG PAIR | eBay

Fit, & ride, are excellent, but , my ABS & ESC & traction control, disabled itself just moving up the driveway..

I took the EBCM connector off, to do some testing.
All my HHR wheel hubs show infinite resistance, between the terminals.
The 4 lug hubs show 1.666K resistance.
Also the same results, found at all the hubs, with the connectors off.

I checked a lot of different part catalogs online.
All years of Cobalts, show the same part# for the 4 lug rear ABS wheel hubs.
All years of Cobalts , & HHRs show the same part# for the rear 5 lug ABS wheel hubs.

So, physically, all Cobalt / HHR rear hubs , interchange, perfectly.
After all, the HHR is really just a fancy Cobalt station wagon...

So, I'm guessing that the 4 lug hubs, use a totally different electrical sensor setup ??
If this is so, then, when 4 lug , & 5 lug Cobalts went down the assembly line, they got
different ABS control units ??

But, when the Cobalt guys switch from 4 lug, to 5 lug, setups, do they swap out the
ABS control units ??? I haven't heard of this being done ??

I do remember a post made, about GM switching ABS vendors, in 2008, but,
all parts catalogs show the same part#s, for all year Cobalt wheel hubs ??

I just don't know what's right or wrong anymore.
Even my 2009 HHR service manual shows the I should have 850-1350 ohms of resistance,
on my stock hubs, that show infinite resistance ??
My service manual even showed wrong pinouts, for troubleshooting the EBCM.

843de

What a can of worms to open in search of a reduction in rotating mass, and getting the ABS and traction control to function properly may be nearly impossible.

While the hubs may interchange, there are some fairly big differences between the HHR and a Cobalt, just because they are both based on the Delta platform, an HHR is not just a fancy Cobalt station wagon.

You are correct in your supposition that there are different brake controllers used between 4 and 5 lug Cobalt models, also different brake pressure modulator assemblies, master cylinders, etc.

With the new hubs, your HHR isn't seeing the signals its looking for, hence the loss of ABS function etc. Can you retrofit an ABS brake controller, modulator, and master cylinder from a Cobalt to an HHR, no idea really, and no idea if the Cobalt controller would be able to "talk" to the rest of the HHR's systems.

You might have to live with the lack of ABS and TSC, or switch back the original OEM hubs and find somewhere else to shave some weight off.

2005HHRauto

Not really, 'a can of worms'.
A 'can-of-worms', would be a 'Rat-Rod'.
The things that they think of, & do, are just totally awesome...
http://rat-rod.us/
Customs can be a 'can-of-worms' too
http://www.youtube.com/watch?v=sEmeXIkT2Dc



It's a done deal on the rotating weight loss reduction.

Two easy options that I know would be to simply redrill the rear stock hubs too,
or to replace the sensor, inside the rear wheel hubs, as long as the 'hard' parts inside the hub, are the same.

I'm sure that the brake controllers & brake pressure modulator assemblies, are
probably the same, between both 5 lug Cobalt & HHR.

Since alot of stuff is the same, it's weird that they would use a different wheel
sensor signal, setup, on the 4 lug Colbalt.

Snoopy

I think your weight reduction will require a visit to the dealer for a "reprogramming".....if they will do it. IIRC (but maybe not), the brake system "balance" is handled and controlled by the PCM, BCM. I would think by exchanging parts it would change and require a "rebalance".....but again, maybe not.

2005HHRauto

No more trouble than changing your oil...

Hmm, Like I said, just a simple redrilling of the rear hubs too, or changing out the 'hall' effect switch in the hubs.

Someone on another forum stated that the 'count' is different, so time to drill stock hubs...

The lightweight wheels/tires have been on the rear for a couple of days now.
It's wonderful how much better the 'ride' is , on 15" rims.