Service Engine Soon light randomly turns on and off

[woodworker88]

Hey, I have a '99 7.3 double cab swb 4x4. Lately, the service engine soon light has been intermittently coming on and turning off. There's no pattern to when it turns on or off. It will come on for a few seconds then turn off then maybe come on ten seconds later or maybe ten minutes later for a few seconds. It never stays on more than a few seconds but continues to turn on and off randomly. The engine is not misfiring and there is no noticeable performance issues. Any help would be appreciated

[Justin@DP-Tuner]

Have you tried to read codes?

[jermcd]

Originally Posted by Justin@DP-Tuner

Have you tried to read codes?

take it to any autozone or advance if you dont have a scanner. codes stay stored in the computer.

[NoRalPh]

Don't bother with that scan....

AutoZone, and None of the other Parts Stores, have the right equipment to scan our trucks All they have are Generic OBD-II scanners and we are Not, strictly, OBD-II because of the GVRW. You need a professional scanner to be able to do a proper job of it.

[woodworker88]

Ok, Autozone scan came up empty handed so i paid a guy 20 bucks at the dealership to scan it with his snap-on. It read codes P0475, P0603, P0478, P0470, P1271, P1273, P1278, P1293, P1294. The problem is not a loose UVCH, I pulled the valve covers and did the 50 cent mod but they were tight before i did the mod. But, like an idiot, i didn't check the rest of the wiring while i was in the valve covers. Also, the IDM is new according to the previous owner and confirmed by me when i pulled it out today to check. Any help would be much appreciated. Thanks!

[woodworker88]

Everyone who thinks they might have a loose UVCH: please google GB tech bulletin 103 and perform the simple test on the connector that goes to your IDM. It will keep you from having to pull the valve covers. Test will tell you if you have loose/damaged uvch, bad injector solenoids, or any short circuiting of injector wires. To access your IDM: remove drivers side wheel well, look to your right under the body panel and use a 10mm socket to remove the idm connector.

[Ressurektion]

Originally Posted by NoRalPh

Don't bother with that scan....

AutoZone, and None of the other Parts Stores, have the right equipment to scan our trucks All they have are Generic OBD-II scanners and we are Not, strictly, OBD-II because of the GVRW. You need a professional scanner to be able to do a proper job of it.

Any parts guy worth his salt can use the generic testers to find the stored memory codes. You just need to know where to look.

If you are ever near an O'Reilly, their scanners can find the stored codes. You just need to find an operator who can find the right test.

One thing I noticed with my truck, if I didn't have the memory erased properly, or with the correct tool, the light would flicker. Stopped at my dealer and had them clear the memory, now it doesn't come back on randomly.

[NoRalPh]

Originally Posted by Ressurektion

Any parts guy worth his salt can use the generic testers to find the stored memory codes. You just need to know where to look.

If you are ever near an O'Reilly, their scanners can find the stored codes. You just need to find an operator who can find the right test.

One thing I noticed with my truck, if I didn't have the memory erased properly, or with the correct tool, the light would flicker. Stopped at my dealer and had them clear the memory, now it doesn't come back on randomly.

Doesn't work like that for us though....

First, the protocol on our trucks is actually called SAE J1850 PWM (NOT OBD-II Standard)

Next, because it's a Diesel with it's own set of non-generic codes, PLUS Fords proprietary codes that have to, sort of, be Reverse Engineered to figure-out what they mean (and NONE of the Generic loaded readers have ANY of these) those scanners don't work right.

So, in the end, nobody can be enough "worth his salt" to know "where to look" in one of those scanners to find information that doesn't exist there

Now that's not to say that there are many generic codes that are in our computer that can be pulled. Sure, you can often get something that's hopefully relevant, but more often the case is they comes back with "No Codes Found". When in fact, a good scanner pops them right up. For the Generic, there's no Magic about it, it's just NOT in their Library....