Which OBD II protocol does a '97 Camaro use?

Can anyone here confirm that the '97 Camaro Z28 uses the ISO protocol in addition to VPW? I'm getting a OBD II code reader and I'd rather get the ISO version than the VPW, but it needs to work on my Camaro. This site lists my car as the only Chevrolet to support ISO, all others are VPW:

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However, this more professional looking site doesn't mention it:

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I'd like to be sure so I don't buy something that doesn't work.

Thanks,

Ulf

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Reply to
Ulf
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The 97 Camaro NEVER used ISO.

It is J1850 VPW 10.4k like all other domestic based GM vehicles built until 2004 MY. They are now switching over to CAN (internally called GMLAN High Speed).

Reply to
saeengineer

I dont know offhand what the Camaro uses, but I had some comments:

Although cars can speak multiple protocols internally, they are supposed to answer OBD-II on one (and ONLY one) protocol, per various regulations. So if the car is compliant, you won't be getting OBD-II response on multiple protocols.

One solution is to get a PassThru (J2534) compliant scantool supporting all protocols, and use SAE J1699 for auto-discovery. The J1699 document specifies a CARB/OBD-II compliance test; it involves opening each protocol in succession, to determine which one the vehicle uses. Although you must buy the SAE's J1699 document, there's a free open-source implementation of the spec available at

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This requires a PassThru (J2534) compliant scantool, which hooks your laptop up to the car. It's more expensive than an average $40 codereader, but for an independent garage or a car enthusiast it's something worth considering. That way you can programmatically reflash, calibrate, and coderead for J1850VPW, J1850PWM, CAN, ISO 15765, ISO 9141, Chrysler SCI, and other protocols using just one device.

-joey

Reply to
Joey Oravec

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