Jump to content
CaddyInfo Cadillac Forum

SES Light and Trouble Code


Recommended Posts

For the past three days, my Service Engine Soon light has come on within 10 minutes of starting the car. The only current DTC showing is PCM P1860. When I clear the codes, this code resets within a minute or two, but the SES light doesn't always come on until later. If I am reading the code correctly, it means TCC PWM Solenoid Circuit Electrical. This code appears to be in a grouping with transmission related issues. In fact, PCM PO741 was also displayed as current the first time the light came on. I have not observed any changes in transmission performance or shifting. Should I just ignore this? Thanks!

Link to comment
Share on other sites

It sounds to me like one of the transmission solenoids is checking open. I would check the electrical connectors to the transmission, reset the codes, and see if that fixes it.

-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

Link to comment
Share on other sites

Join the club. there are a few of us with the same issue. SES light on and codes 1860 and 0741 but no driveability issues with the tranny . no one here has been able to pin point the fix yet. some people on this forum have told me there could be a wiring issue since the tranny isnt acting up. I havnt had time to ck it out yet. please keep us posted if you find the fix.


2002 STS

Link to comment
Share on other sites

P1860- When that code is set the car might lock you out of overdrive (4th Gear) and will not engage the Torque converter (under most circumstances). At about 40-43MPH you should feel or see a small drop in RPMs much like a shift, if you don't your TCC is not locking up.

What causes the DTC to be set is either power stuck on or the line is stuck grounding out. My manual lists as possible causes: A bent terminal, A backed out terminal, A damaged terminal, poor terminal tension, a chafed wire, a broken wire inside the insulation, moisture intrusion.

Also check to make sure the Transmission fluid is at the right level.

Help this helps you find the problem.

For you other check to make sure none of the lines between the radiator cooler and the transmission are pinched. That DTC will set when your transmission in in hot mode, which will also cause the 1860 code to kill 4th gear on you.

The Green's Machines

1998 Deville - high mileage, keeps on going, custom cat-back exhaust

2003 Seville - stock low mileage goodness!

2004 Grand Prix GTP CompG - Smaller supercharger pulley, Ported Exhaust Manifolds, Dyno tune, etc

1998 Firebird Formula - 408 LQ9 Stroker motor swap and all sorts of go fast stuff

Link to comment
Share on other sites

Well, I played around under the car yesterday, and didn't find anything out of place or damaged, although it is impossible to visually trace the wiring harness right to the transmission. I wasn't about to disconnect anything that I could feel, but not see, in case I couldn't get it plugged back in again. I cleared the codes, and after a 30 minute drive, got the SES light, and PO741 and P1860 again. By the way, it does shift smoothly into overdrive. As I said earlier, there are no driveability issues. I guess it's off to the transmission shop tomorrow morning. I don't know how much time they spend trying to trace and locate electrical problems in the wiring before they tear into the transmission, as I know the money is to be made in the R&R's, not in finding shorts or poor grounds. What works in my favor is I have dealt with this guy before with my '97 DeVille when it was shifting harshly, and it turned out to be a relatively inexpensive shift solenoid. He could have pretty much told me anything, as the car had 150K on it at the time. However, I went into the shop armed with enough knowledge that he could see I had some idea what I was talking about. Hopefully that method will work again tomorrow.


Link to comment
Share on other sites


This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

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