I would like to find out what error codes e26 e27 e52 mean on service soon of 1986 Cadillac Deville

Question edited for clarity, spelling of the maker, toss in some CAPS and make sentences.
Question moved to model category.

Both are Transmission errors

E-39 Error

https://caddyinfo.ipbhost.com/topic/10886-92-deville-error-code-e39/

and E-98

Diagnostic Code -- E98 Need Help

Cadillac Owners Forum https://www.cadillacforums.com > threads > diagnostic...
Nov 9, 2005 - E98 - High RPM P/N to D/R in ISC Range check your tranny. its sometimes called a VCC overstress error. dont change gears until car is totally ...

Great, now I have MORE trouble codes!! E91 and E98
Aug 7, 2006
Error codes E22, E32 E52 E98 - Cadillac Owners Forum
May 5, 2004
More results from www.cadillacforums.com

Very likely it could be a crankshaft position sensor if you can fire it up and runs for 20 seconds and shuts down it could be your problem which if that is one of the error codes after a scan it can trigger other codes with that one faulty sensor

E26 and E27 which is "Shorted throttle switch signal" and "Open throttle switch signal".
The code E52 just means that the ECM lost power or ground or that someone forgot to clear the code after hooking the battery back up. It could mean a bad computor but not very often. 2 things that come to mind is a bad ignition key or lock cylinder or a faulty neutral safety switch. Try the other ignition key first. Then with your foot on the brake pedal hold the key in the start position and move the shifter slowly from P to D. If it tries to start then the NS Switch is bad or out of adjustment. If it still won't start then you will need to troubleshoot the ignition key/PASS KEY system for an open wire in the steering column. Hope that helps. Bill

e 44 is oxygen sensor signal lean e52 is pcm memory reset

check fuel pressure

E52=memory (history) has been lost.try ERASE all your codes and see if any come back.1.turn Ignition ON, Engine OFF.2. Push and hold the OFF and WARMER buttons until all the segments on the display illuminate and as soon as the codes start to appear, Push the OFF and HI buttons and release them until you see .7.0.
3. Turn ignition OFF.

E26-shorted throttle signal switch
E32-open MAP sensor signal
E70-Intermittent TPS signal
E97-High RPM P/N to D/R Shift

some could be history codes not currents tho maybe try to clear then drive it and see what comes back.
Press off and high simultaneously to clear codes
and this link may help
http://www.cadillacforums.com/forums/ht4100-4-1-4-5-4/21558-obd-i-codes-4-x-engines.html

e52 is ecm memory reset
e91 park neutral safety switch
e98 transaxle shift fault

"service soon" is a reminder that it needs regular maintenance, and usually the dealer has a tool to reset that light on the dashboard, which can be expensive to buy.

If you do all the maint yourself, and you know that all the fluids have been replaced or capped off, you could cover the light with a piece of black electrical tape, then go on with your life.

E40 is a problem with the Power Steering Pressure switch. Most probable cause is that if work was recently done, someone forgot to put the wiring harness back on the pressure switch. The pressure switch is usually mounted on the high pressure line. It looks similar to an oil pressure switch. If the wiring is correctly installed, the switch is probably bad (assuming that your power steering works).

E52 is a PCM (engine computer) memory reset code. Have you disconnected the battery of late? If not, check all your fuses. One of the fuses for the PCM may have blown.
Charlie