code p0743 help!!!

I have everything working on this '98 neon except for a shutter at idle along with a DTC p0743. This refers to a torque converter solenoid problem of some kind, but how can I diagnose this. Can I assume that the shutter (maybe caused by low rpm) is due to the torque converter locking up when it shouldn't be? Also, what do i have to do to replace the solenoid? Do I have to drop the transmission? Is it time for a junk yard swap?

Thanks in advance for your thoughtful ideas!

This may help...
Hi, Ive messed with this code plenty of times before so this is what you will have to do. More than likely if it keeps coming back on then your TC solenoid is going bad and will have to be replaced. The TC solenoid sits on top of the valve body inside the tranny. You are going to have to drop the tranny pan, take the valve body out, and replace the TC solenoid. Also if your doing this your self I would go ahead and change the tranny fluid too because you will lose most of it while doing this task.

The shudder at idle is more than likely your front motor mount going bad.

My 1998 is bad and will be replaced ASAP.

How can I tell if it's the front mount or not? The mount looks ok.

have someone hold the brake and shift through gears while you watch the engine. excessive engine play is pretty easily noticed.

You will have to look through the rubber mount and look for tearing.

All stock front mounts will wear out between 60,000-100,000 miles guaranteed.

You will have to look through the rubber mount and look for tearing.

All stock front mounts will wear out between 60,000-100,000 miles guaranteed.
I took the front mount off and sure enough it was torn. I've ordered a new one which will be here Tuesday. I'll post how it turns out. I also ordered a new lock-up solenoid due to the p0743 code. Hopefully this will complete the repairs on this car. You guys are the best! The help has been great!

Glad to have helped you.

Tell us how it goes.

Well, the shudder is still there after replacing the front mount. I did get rid of the CEL after replacing the torque converter lock-up solenoid. The tranny continues to shift a little funny, like it switches between 1st and 2nd a lot and also revs pretty high in 1st before shifting to 2nd. not sure what to do next. I've sunk some pretty good $ into this so far.

How is your fluid level? What fluid did you put in there?

Bands need adjusting.

http://www.neonspeed.com/howto/howto_1stgen_atxbandadj.htm

Do you think it's the kickdown band or the low/reverse band? I did adjust them when I had it all apart, but I might of screwed it up somehow. My torque wrench doesn't accurately measure torque levels that low.

Sometimes I don't think straight when I'm flat on my back looking up at those red drips coming at me.

Do you think it's the kickdown band or the low/reverse band? I did adjust them when I had it all apart, but I might of screwed it up somehow. My torque wrench doesn't accurately measure torque levels that low.I doubt it's your bands, but it would be the kickdown band not the reverse band. What fluid did you put in the tranny?

I doubt it's your bands, but it would be the kickdown band not the reverse band. What fluid did you put in the tranny?
I used ATF 3+, 4.5 qts. Normally I would have added just 4 qts per spec, but since I had the valve body off, about a half quart drained with that. The level is right where it should be.

I used ATF 3+, 4.5 qts.Mopar ATF+3?

Yes, Mopar ATP 3+

I've convinced myself that the transmission is toast, but the engine shutter still concerns me. I've replaced the front engine mount and the shaking at idle is still bad. Once the rpm's go up, the engine settles out nicely. What else can cause this vibration at idle?

Could be IAC, TPS, throttle cable?!?! Check for vacuum leaks and or exposed wires. Some wire could be grounding/shorting out causing bad vibrations. I saw a guy spend $3000 on parts and service for a vibration, turned out is was a bare wire on the wiring harness under the PCM that was causing his problem.

Your torque convertor is not disengaging. Which can cause the idle vibration.

So, how can I tell if this is the case?

Lack of power and shuddering off the line would be a good indicator, plus the code.

Your torque convertor is not disengaging. Which can cause the idle vibration.It only kicks on at around 45+MPH, I think, and would it cause vibration? I would think it would stall the car out.

Lack of power and shuddering off the line would be a good indicator, plus the code.
The vibration is at idle in park or any gear. Once at a higher rpm the vibration disappears. Also, when I replaced the torque converter solenoid, the code disappeared. I'm now code free...just not shake free.

I am just curious, when is the last time you replaced your spark plugs and with what kind?

The vibration is at idle in park or any gear. Once at a higher rpm the vibration disappears. Also, when I replaced the torque converter solenoid, the code disappeared. I'm now code free...just not shake free.

I just went through this myself, it was a failed torque convertor out of balance.

I just went through this myself, it was a failed torque convertor out of balance.
So how can I test for that?

Before we go down that path, just one more thing to check,m have you checked your side motor mounts?

Your tranny mount?

I am just curious, when is the last time you replaced your spark plugs and with what kind?
Interesting question. The previous owner reported the #2 spark plug had been ejected from the head and stripped out....supposedly repaired. When I tried to replace this plug, it looked like it was bonded in with epoxy or something. I bought a thread repair tool and solid inserts along with a fresh supply of Champion plugs and I'll have a go of it this weekend. While I have them off I'll do a compression check too.

Interesting question. The previous owner reported the #2 spark plug had been ejected from the head and stripped out....supposedly repaired. When I tried to replace this plug, it looked like it was bonded in with epoxy or something. I bought a thread repair tool and solid inserts along with a fresh supply of Champion plugs and I'll have a go of it this weekend. While I have them off I'll do a compression check too.Keep us posted.

This is not good. At idle I individually pulled the plug wires and I got no response with #2 cylinder althought there was spark. I then did a compression test: 155, 0, 165, and 175. Looks to me like the #2 cylinder is a little low. (HaHa)This is the cylinder with the problem with the damaged threads. I tried to use the nifty thread replace insert tool, but the socket needed to re-tap the hole interferes with the head. I'm convinced the threads aren't the only problem. I was able to get the compression tool to thread in OK so at least is should have shown something. Any ideas on what to do next? Maybe swap engine/transmission from the wrecker yard?

IMO, you should fix the threads in the head and see what happens. If you have to remove some parts to do that or get a special tap, so be it. I bet the compression tester didn't seal and that's why no reading. If the head is not possible to fix, get a new head, not a totally new engine.

I bet the compression tester didn't seal and that's why no reading.I was able to get the compression tool to thread in OK so at least is should have shown something.If you in fact have 0 compression then it's really possible that you have some bent valves. Definitely try to get the threads fixed, if not get a new head as Brian R. suggested.

Or this could be an opportunity to do a 2.4 swap :grinyes:

If you in fact have 0 compression then it's really possible that you have some bent valves. Definitely try to get the threads fixed, if not get a new head as Brian R. suggested.

Or this could be an opportunity to do a 2.4 swap :grinyes:

I'm in the process of taking off the head. That will allow for inspection of the valves and fix the threads on the #2 cylinder. when re-assembling this thing will I need to replace the head bolts? Is there a way to tell if the bolts are OK? I'm trying to do this on the cheap.

I'm in the process of taking off the head. That will allow for inspection of the valves and fix the threads on the #2 cylinder. when re-assembling this thing will I need to replace the head bolts? Is there a way to tell if the bolts are OK? I'm trying to do this on the cheap.

I'm F'd. I just took the head off to discover a hole in the #2 piston. Now, is it time for a junkyard engine or can I just replace one piston or do I have to pull the motor or what? I'm kinda bumming about it. The head itself looks fine.

I'm F'd. I just took the head off to discover a hole in the #2 piston. Now, is it time for a junkyard engine or can I just replace one piston or do I have to pull the motor or what? I'm kinda bumming about it. The head itself looks fine.You can replace just the piston if you like, but I'd replace all four. If you have a SOHC engine put in some DOHC pistons for better compression. Do not reuse the head bolts...GET NEW ONES!

IMO, compare prices for replacing the piston with replacing the engine with a used one. Whatever is cheaper.

You can replace the pistons without removing the engine by removing the front engine mount, and gaining access to the rad bearings through the oil pan.

Fairly straight forward.

You can replace the pistons without removing the engine by removing the front engine mount, and gaining access to the rad bearings through the oil pan.

Fairly straight forward.

This is what I'm thinking...I can get a piston at NAPA for about $45. I can get a ring set for about $85. I can open the oil pan and push the pistons up through the top, use one of those hone tools that go on a drill and hone the cylinder walls of all 4 cylinders.... At the same time, I'll take the head to a place I know of to get an insert installed in the #2 cylinder. Then I'll put it all together with a new head gasket and head bolts and maybe all will be well.

I'd be tempted to get the valves ground and valve seals replaced, but I'm trying to do this on a budget. Is this what I should do? You guys have provided some great comments in my time of pain!

The other option is a used engine for $400.....