View Full Version : 4100 Service Now / Codes

10-07-12, 10:14 PM
I'm new to this forum and glad to be here. I must say I have found alot of helpful information. I have an 84 Eldorado Biarritz with 73000 miles on the original 4100 engine. About 2 weeks ago my Charge Light came on and the Service Now light lit occasionaly while returning home from a car show. Once home, I checked alternator output. It was at 13.2 volts. Replaced alternator, voltage back up to 14.5. Charge light off and no Service Now light. Today I drove to another show, no issues. But driving home the Service Now light returned. It would turn on and off and when it would turn on I noticed either a rev in the engine or what sounded almost like a downshift/higher rpms when at highway speeds. Side street driving would get occasional light, but no revving feel. Checked codes and I get a 16 and 52. Both seem ECM Related. Before ordering and replacing the ECM I figured I'd give the forum a try for some assistance. I only put about 500 to 1000 miles on this car per year. Strictly cruise night / car show fun.
Thanks for any help I can get.

11-07-12, 09:08 PM
Tighten the smog pump belt.

12-16-12, 01:09 AM
I have a 1984 eldorado biarritz that has the "stop enine oil pressure" light blinking and "service soon" then "service now" light on it idles high sometimes then will die I drove it to my after I bought it and it'll shut off when I slow down or stop. It also reads codes 19 20 24 26 27 52 53 what do these codes meann and how do I fix the problem with it shutting off and idling the way it is


Thanks I will do that first thing in the morning any other suggestions or reccomendations

12-16-12, 10:17 AM
First thing I would do is replace the oil pressure sender by the oil filter with a oil pressure gauge to verify correct oil pressure. If the pressure is about 6 or 8 LB at idle then the oil pump is ok. If not, remove the distributor to inspect the oil pump drive gear. This engine had a habit of wearing out this gear. If the teeth on the gear are razor sharp it's worn out, replace it. Regarding the codes, erase all of them and if the service engine soon light reappears, then repost them. 19 is shorted fuel pump circuit, 20 is open fuel pump circuit, 24 is a fault in the speed sensor signal. 26 is a shorted throttle switch circuit. 27 is open throttle switch circuit. 52 means the battery has been disconnected in the past. 53 means the signal to the distributor was interrupted. If the codes display only 2 times, they're history and have no meaning now. If the code displays 3 times, the problem is occurring now and must be diagnosed. And this should have been a brand new post ideally. Good luck! And buy the factory service manual! best money you'll spend whether you fix it or have someone else do it.

01-05-13, 07:43 PM
And I guess its still not fixed? To help others, complaint, cause and final correction should be posted.

Cadillac Cust Svc
01-06-13, 01:38 PM
Hi Vinnie & Joseph,

Like carnut, I'm also wondering if you were able to resolve your concerns. Posting here may benefit other community members with similar questions. And if you're still having concerns, please do let us know!

Cadillac Customer Service

01-12-13, 09:37 PM
So sorry I been really busy working but I jacked the car up inspected it really close n found that the oil pressure sensor was rigged up with a sensor that didn't go to it then the wires were stripped and were just wrapped around the sensor until it vibrated off I'm assuming and that's when the people I bought it from just parked it and put a for sale sign on it. The codes are still showing I tried resetting the car but oil pressure light is on now(not blinking) and service now light is on (not blinking)