D.D.

So, after reading MANY postings, which Interstate battery is the one for my 997 C4S? Is the MTP-91 correct on all counts? Or is it the H-7 or H-8 the best direct size/replacement? Battery just died.......

Thanks.

JasonKM

Direct replacement is either H7 Interstate or any Group 94R battery. This is a common battery for European cars and some Chrysler models (300 and Cherokee).
Best bang for your buck is the 94R battery from Wal-Mart for about US$80. 3 yr replacement and 9yr pro-rated warranty. It's made by Johnson Controls and has more cranking amps than the OEM battery.

On the 94R simply insert the vent hose and fitting on one side and you can pull the plug from the other side from the stock battery and insert it into the vent on the other side

JasonKM

should also mention that you will get a PASM error when you reconnect the new battery. This will go away once your drive the car a few miles

jhbrennan

Ditto on the Wal-Mart MAXX 94R - a real value and exact fit.. You might also have to reset the windows but that's pretty simple - described in the manual.

TerpsRED

+1 on the MAXX 94R. Simple Drop in exact fit and great price. 3 year warranty as well.

D.D.

Went with the Wal-Mart battery...........easy fit......Got the PASM code, but have not driven the car yet.

Thanks for all your help..........

Dale

No HTwo O

You should NOT be getting a PASM warning, you should be getting a PSM warning.

PASM- Porsche Active Suspension Management
PSM- Porsche Stability Management

cab&coupe

Jason, good to know. Thanks for posting.

D.D.

Correction......PSM warning light.