For awhile now my check engine light has been on. I decided to read my codes this morning just to see what was going on. Below is my codes.

12 (RPM Signal)
13 (RPM Signal)
14 (Ignition Signal)
25 (Air-Fuel Ratio Lean Malfunction)

I'm sure code 25 is caused by a open exhaust without a Cat Convertor.

12-14 I have no clue.

I'm going to reset the codes in a few and drive the truck to see what pops up. I've never reset these and I changed motors out about 4,500 miles ago. So some could be old I dunno. But in the mean time could you guys fill me in with some info. Thank you.

By the way this is on my 1993 pickup 22re

 

581 posts and you've never come across a reference to the Service Manual?

Well, here you go: http://personal.utulsa.edu/~nathan-b...26diagnosi.pdf

The NE signal comes from the distributor, IGF from the ignitor. Does your truck run?

Code 25 is unlikely to have anything to do with your Catalytic Converter (or lack of one), because the sensor is upstream of the converter. So you're running too lean, or have a problem with the O2 sensor.

 

You have something up with the distributor and the signal generator. Check the air gap make sure your magnet is not gone. I would also check the rotor and make sure there is no play in the shaft.

Next is something to do with the ignitor and or coil. There are resistance checks that can tell you if there good or not. FSM will be the place for those.

Next is the lean condition. You have unmetered air entering after the AFM. Check the intake piping and vacuum hoses on the throttle body for leaks.

 

Of course it runs. I drive it every single day. It runs really good. Pretty peppy for a new engine. However I was curios about those codes that's why I asked.

And nope never ran across that reference. I've never asked a question like this lol. I'm kinda a do it myself kinda guy and I really don't ask unless I have to. I know these trucks really well. However I've never dealt with these codes or Check engine light to say. I've always ignored it do to my trucks being for recreational use only. However this one is my DD so finding out these little problems is a must.

I have a build thread on this truck. Your more then welcome to check out and post. I've also just posted pics in the IFS flex thread.

 

You know I may be onto something here. About 3 weeks back my wife asked me why my tach was reading around 4.5 at 70mph. I told here I didn't know. A few moments later my tach dropped nearly 1 grand. So I may have a small electrical issue here. I didn't think of that before but once I read your reply it kinda hit me. I may be wrong but its worth looking into. The truck has never quit on me except for when the timing chain snapped. Other then that its been great even yet to this very moment.

 

Well as I stated I was going to reset the codes. Once rested I drove my truck right at 32.8 miles. No check engine light so I'm assuming those were old codes. During that 32 mile trip I shut my truck off multiple times and I'm assuming that I'd there was something wrong then I would've pulled a code within that trip. So as of right now I'm good. I will keep ya up to date just to see what happens tomorrow