Alien Codes

[Paul S]

My friends daughter is considering buying (and this may be a dirty word on this webbsite) a BMW because it is a convertible and He was wondering if there is anyway to check the OBD's on it before she buys it. It is an '02 330CI.

On the same subject I wonder if Cadillac would ever consider re-introducing the convertible? I know it did wonders for Chrysler when Lee Iococa brought it back, but that was a long time ago and times do change. At any rate any help would be appreciated.

[Cadillac Jim]

I would suggest that your friend's daughter get a CarFAX account and check the VIN of any car that she is seriously considering. As far as the OBD codes, you will need a code reader. All cars sold in the USA since 1991 have an OBD connector under the dash on the driver's side. If you ask to have the car inspected by a mechanic, that will do, just pick a mechanic that has a really good code reader and make sure he uses it in the inspection.

[Logan]

It should be noted....with OBDII....most the codes are the same if the car is a GM, Ford, Honda, BMW etc.

Example...PO300 is a random misfire in all of them. PO301 would be 'cylinder 1 misfire'.

Before OBDII....everyone had different codes and different names for the parts.

In the old days..some might call it a 'coolant temp sensor'....others would call it a 'H2O thermo trend detector'.

There are generic codes...and there are manufactures specific codes.

So the misfire codes are the same on all. But something like a air pump code, might not exist on a Honda that may not have a air pump.

[Paul S]

Thank you all for your response. I guess I was hoping it had something similar to my car ('99 STS) where you hold down the two button until the display goes into diagnostic mode and starts revealing any stored codes.

[Logan]

I believe the Cadillacs were unique in having the on board diagnostics mode. Seems I remember some Olds Auroras having a similar mode. I think even Cadillac has done away with the feature on newer models.

You can buy a cheap OBDII code reader for a little over $100.

[Cadillac Jim]

The $100 class of code readers usually, but not always, reads only Pnnnn (ECM/PCM) codes, often only those related to emissions that are important in passing emissions inspection, the raison d'être ror such readers. I ran into this problem several years ago when I had a problem with my EBTCM and found that my hand-held meter was blind to its codes. I got a laptop-based code reader with an OBD-to-USB cable, which runs from $200 to $400 and up, depending on the capability you want. That's why I recommended that you get a mechanic to inspect the car that includes a "pyschoanalysis" with a good code reader.

You might try a BMW dealer service department, but with a car as old as a 2002 model, that may not be the best option because they may not have a tech available that is really familiar with that model the day you bring your car in, and it may not be possible for them to offer the service at a price that is reasonable to you - or at all, if their insurance or management feel that there is an implied warranty in performing a used car inspection service.

I did a web search on "used car inspections" and came up with a number of services, most of which seemed credible. This will cost you about $150, which is money well-spent if you only do it once or twice for a nice car like the 2002 BMW 330 CI. If what is discovered leads you to turn a car down, the investment is returned many times over, instantly.

Please note that I am giving this advice as valid for any make, including Cadillac. You can get a quick read of the car's problem by using the on-board OBD code readout from Cadillacs at least as old as the 1991 model year, and some information on the engine and electrical system from any GM make from the car's ALDL by shorting pins and counting flashes from the "check engine" light back into the 1970's model years; see FSM or even a Chilton's shop manual that covers the model year of interest for some coverage of this.