: No 24x Refrence Signal

02-24-08, 04:06 PM
I am getting a SERVICE VEHICLE SOON on my info center display after the last arctic cold snap.Its a 4.6 93 ELDO ,my PCM codes are PO25,PO23,PO30.The engine runs ok with an occasional miss at idle other than that the enginel has good power and accelerates fine. I took to a friend at NAPA and they did a diagnostic check and said they got the same codes and found all cylinders are getting a week spark signal.

He was also shocked when he puled a plug and found cheap MOTOR CRAFT
Plugs and wires.This was the previous owners Tune Up.That he was telling me about when I repurchased the car 2 years ago.

TOM at NAPA recomenns a new ICM and possible one or all coil packs be replaced saying cheap plugs are known to burn out ICMs and coils.Then move on to to other codes if they are still present.Of course all replacement parts would be AC/DELCO including NEW PULGS .
I have also found that it could be the PCM.

Am I on the write track with this repair before I START BUYING PARTS?
Any help or feedback would be appreciated.

02-24-08, 09:42 PM
Seems like nobody wants to touch my post so Ill update it.From my research thus far .The shop manual says it could be caused by three things.ICM,PCM,or
crank sensor.$25 for a crank sensor which will be my first shot.

I find it hard to believe the ICM is failing as well as the car is running.

PCM will be my second shot.

02-24-08, 09:55 PM
Not ignoring you. Just no ideas. Sorry. Maybe one of the techs will chime in.

03-09-08, 10:42 AM
Ok sorry Ive been out for a hile. Ill take this one on . If the ICM is not putting out the 24X signal there is one of 4 possabillities. as mentioned before 1 bad ICM but at over $400 this would be the last thing Id throw at it. or any 1 of these three sennsors. crank A, crank B, or your cam sensor. if you lose any one of these three your ICM will drop out the 24x signal prompting a MIL. Your car will still run fine as any two of the three sensors are needed for funcionality. if you are still recieving a cam out puse from your ICM then that would further narrow it down to crank A or B. and since these are the same part or further only $40 just buy both and be done

Happy motoring:yup:

03-10-08, 02:37 PM
Very interesting info, zbuickman - thanks for that. I think I read that you may have to take the car to the dealer to have the crank sensor offset re-calibrated if you change them? Maybe someone else can add something about that.

03-21-08, 02:23 PM
I finally got a break in the weather and found a ICM junk yard $80 w 4coils on it nice deal considering $650 for the shot new.Guaranty for 3 mo.Just threw in the
IMC only, p025 code is gone. :thumbsup:

The bad ICM was causing the following codes,

Thanks everyone for your help and helping me keep my car out of the shop!!!

I also installed the correct spark plugs AC/DELCO Professional platnium .

In the process the starter started failing and did the intake manifold board trick not having to disconnect the throttle body parts.Very easy it was nice not to have to crawl under the car for a starter R&R.