ok, 3 old school diagnostic faults...

Here they are, although the first one is not a fault...

(1) 12* Battery Disconnect Direct battery input to the PCM was disconnected within the last 50 key-on cycles

(2) 22** ECT Sensor Voltage Too High (or Too Low) Engine coolant temperature sensor input above the maximum (or below the minimum) acceptable voltage

(3) 25** Idle Air Control Motor Circuits; or Target Idle Not Reached An open or shorted condition detected in one or more of the idle air control motor circuits; or Actual idle speed does not equal target idle speed


can someone translate that into noobeze!

Check for disconnection or shorted wire to the coolant temp sensor, or bad ground. think that the computer needs that input to control the IAC. pretty sure on a OBDI the only time a code is set for the CTS is when electrical signal is lost, not if the sensor is bad. ask me how i know that!

I am thinking it's a bad ground... was told there are 3 grounds... one from the battery; one from the firewall and one on the oil dipstick... I have 2 the firewall and battery...

got any pics of the grounds... mostly the oil dipstick one?

what year is your Jeep? On my 97, the ones at the dipstick are actually farther forward, right in front of the ignition coil. There are two studs side by side, each with 2 or 3 ground wires bolted to them.

cdnabn49 said:

I am thinking it's a bad ground... was told there are 3 grounds... one from the battery; one from the firewall and one on the oil dipstick... I have 2 the firewall and battery...

got any pics of the grounds... mostly the oil dipstick one?

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Easy enough, although I don't have a pic. Just look at the dipstick handle, follow it down to the bracket bolted to the engine. The stud that holds that bracket up should also have the main engine ground fastened to it.

Alternatively, follow the mains lead from the battery to engine block, and you'll see it there.

5-90 you rock! atriot:

carefully inspect the wire harness at the back of the cylinder head for breaks or chafing. IIRC, both these circuits are fed from the drivers side and the grounds terminate at the dipstick tube bracket via a branch from the same bundle around the back of the passenger side of the head.

(1) 12* Battery Disconnect Direct battery input to the PCM was disconnected within the last 50 key-on cycles

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No big deal obviously.

(2) 22** ECT Sensor Voltage Too High (or Too Low) Engine coolant temperature sensor input above the maximum (or below the minimum) acceptable voltage

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Check the coolant temp sensor. Should be in the thermostat housing. If you have a multimeter, you can check its resistance both hot and cold to see if its within spec. Could be a wiring problem to it as well.

(3) 25** Idle Air Control Motor Circuits; or Target Idle Not Reached An open or shorted condition detected in one or more of the idle air control motor circuits; or Actual idle speed does not equal target idle speed

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Clean the throttle body, including removing the IAC motor and clean the tip and bore that it sits in. If the idle is staying high, it might be a simple vacumn leak somewhere. I understand you can turn the ignition on with the IAC motor pulled out and verify that it moves too.

grounds look good...

checked the coolant level... the coolant cap was scummy??? topped it up... not sure why it was scummy????

"Clean the throttle body, including removing the IAC motor and clean the tip and bore that it sits in." ok dumb question... this is the air intake and where the throttle cables attach?

cdnabn49 said:

ok dumb question... this is the air intake and where the throttle cables attach?

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Are you still getting all the same codes? Swap the IAC with a known good part, or get a cheapie with a 30 day warranty from the JY and see if that fixes yer IAC code. Not sure how much they are new, but it never hurts to replace it with new if it is an old part. (preventetive) The coolant temp sensor is a $20 part and is the easiest sensor on the whole Jeep to replace. I'd swap it and be done with it. When I got that same coolant temp CEL a new sensor fixed it. Ignore code 12, we all get code 12.

A quick writeup on cleaning the throttle body. It's for a GRand Cherokke, but essentially the same steps.
http://www.wjjeeps.com/service/tbody.htm


Rather than throw money at sensors. I recommend spending the $20 to get a meter and learn how to do simple measurements like voltage and resistance. The coolant sensor is incrediblt easy to check with a meter.

Harbor Freight has their $7 meters on sale for $2 every once in a while. They are basic little digital meters that work well for automotive stuff. I bought 30 of them last time they went on sale and sold them on eBay for $10 each. I keep one in each vehicle. I routinely give them away with a free lesson to friends who ask me to check things for them. I have my nice $120 meter and an o-scope for doing electronics.

x2 -- I got the little Harbor Freight meter and it's actually pretty sweet compared to the old Radio Shack analolgs. And there is no guarantee theat the new part is any good either. Throwing parts on cars without proof they are bad is what really gets things screwed up. The original part on the vehicle is usually better than the cheepo replacement part you buy which has never even been subjected to the levels of Quality Control that hte original was subjected to.

winterbeater said:

x2 -- I got the little Harbor Freight meter and it's actually pretty sweet compared to the old Radio Shack analolgs. And there is no guarantee theat the new part is any good either. Throwing parts on cars without proof they are bad is what really gets things screwed up. The original part on the vehicle is usually better than the cheepo replacement part you buy which has never even been subjected to the levels of Quality Control that hte original was subjected to.

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Thats what a lot of people think until they are stranded because they never replace things until they actually fail. There is nothing wrong with replacing a sensor when the computer TELLS you it's bad. especially if it is old, and only a $20 part. I suppose you never do preventative maintenance? That belt is fine, don't waste money on a new one...

EDIT: sorry for the rant, you did say test it... My money is still on bad sensor!

I'd agree it's the CTS sensor in this case is likely bad. I prefer to confirm it first because it might be a bad connection or wiring issue too. Most of the time on the newer cars, the when computer is right when it points to a sensor but every once and a while its wrong. Just saying a cheap meter and a little bit of knowledge can save you money.

Preemptively replacing sensors seems like a waste of money to me. Most sensors in the vehicle are not wear items and don't wear out. Noteable exceptions are the TPS sensor and the IAC controller which do have moving parts and generally just make it run like crap when they go. Oil pressure senders wear out too, but they are not likely to strand you anywhere. CPS sensor problems seem to stem from a corroded connector or wires more than the sensor itself going bad. But year that one can strand you.

Belts, hoses, and tires get replaced when they are worn or look like they need it. I might replace hoses if I'm doing the water pump, but I don't just change them for the heck of it. Again a waste of my time and money.