Jump to content
CaddyInfo Cadillac Forum

Diagnostic "Snapshot"


Recommended Posts

I have heard that Cadillacs have a diagnostic "snapshot" capability to help track down intermittant problems. The "snapshot" records all the engine data when the driver chooses to do so.

I've briefly looked through my manuals and haven't found anything on it.

Can someone tell me how to take a "snapshot" on a '94 Eldorado with Northstar engine and how to get a read-out of the data?

Thanks in advance.


Happiness is owning a Cadillac with no codes.

Link to comment
Share on other sites

Maybe this will help


Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

Link to comment
Share on other sites

The customer snapshot is most likely what you are trying to get. This is performed when NOT in the diagnostic mode.

When driving or idling, and the car is "acting up"; on the Climate Control press OFF and Front Defrost buttons at the same time. It will take a second or two.

When done properly the "Service Engine Soon" will illuminate for two seconds; as confirmation that the snapshot was taken.

Retrieve the data be by entering the diagnostic mode.

After the system has gone through the various systems monitored, select:

PCM / Snapshot

The error will appear as P001 SNAPSHOT

For this information to be useful also note how you were using the vehicle when the snapshot was taken, i.e.; 65 MPH, accelerating, gearshift in D transmission still in 3rd gear, etc.

Any subsequent snapshot will erase the first one.


Drive'em like you own 'em. - ....................04 DTS............................


Link to comment
Share on other sites

Thanks for the responses. The following might be useful or interesting to those of you who are reading this thread. The information works for 1994 and similar years, but I'm sure newer Cadillacs have a similar system.

I finally found the Customer Snapshot information in my Service Manual. (It's in the index - not under SNAPSHOT, not under CUSTOMER, but under POWERTRAIN CONTROL MODULE - Customer Snapshot.) Silly me, why didn't I think of that? <_<

The manual explained something I didn't know before. The PCM automatically takes a SNAPSHOT ON CODE SET whenever a code is set. This snapshot contains readings for the relavent sensors and systems at the instant the code is set. This information can be very useful in diagnosing a problem.

To retrieve this data, enter diagnostic mode by pressing the OFF and WARMER buttons. When the DIC asks PCM? press the HI fan button to answer "yes". Press the LO fan button to answer "no" to everything until it asks PCM SNAPSHOT? Press HI fan to answer "yes". At this point, it will start asking P??? SNAPSHOT? (P??? being the latest codes that have been set) P001 is your Customer Snapshot, but the others will relate to the codes. The readout will be a value then PD?? for PCM DATA or PI?? for PCM INPUT. Press HI fan to move on to the next item or LO fan to go back to the last. A discussion of each PD or PI item can be found in your Service Manual along with its normal range of values. If your Cadillac has a problem, this system lets you dig deeper into the computer's memory to find out exactly what is wrong.

Cadillacs are complex automobiles but I've always known the on-board diagnostics go a long way to help figure out what's wrong. I just realized the system does a whole lot more than I thought. I'm impressed!


Happiness is owning a Cadillac with no codes.

Link to comment
Share on other sites

  • 13 years later...

@Poobah  when you were researching snapshot here, what year northstar did you have?

Did you have any luck?

I think it was possible to access it prior to 96, but not after 95, correct?  With OBD2 after 95, you need a TECH2, no?

What did you find out. 

PS, hope all is good, Mike

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Create New...