Fault Code O0201 - rough idle

[branny]

Running on the highway today i got the check engine light.
The engine had been, very slightly rough, not really anything to speak of.
The code was P0201, and with the check light the idle after stopping got very rough.
I felt like i could 'rev out of it' and it would run ok again.
P0201 = Injector #1 Control circuit.

I put a bottle of fuel cleaner in and went home, but i doubt that fixes anything.
So, where do i start?
Which is cylinder #1?

Thanks!

 

[teeje]

So you were right on trying that fuel cleaner as that code is cylinder 1 injector circuit malfunction. Check the connections under the hood and make sure something hasn't worked its way loose. Start there someone else will post another suggestion soon I'm sure of it! Good luck.


2002 Jeep Liberty 3.7L with brand new engine
Sent from my iPhone using Tapatalk

 

[branny]

The code went away after a few starts.
I can see this being a difficult thing to troubleshoot so I will continue to monitor before spending money.

If anybody has had a similar experience, please let me know.

The code is p0201

 

[uss2defiant]

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[LibertyTC]

Take some compressed air and blow out the #1 disconnected/connector and clean contacts at injector with alcohol.
Look for any chewed up wires etc..

 

[branny]

Take some compressed air and blow out the #1 disconnected/connector and clean contacts at injector with alcohol.
Look for any chewed up wires etc..

Thanks, that's what I'll be doing this weekend.

 

[branny]

Well, I cannot replicate it or find/induce any problems at the coil.

My wife drove it today and on a slightly longer journey it started playing up, misfiring code 201 and just very rough.

Has anybody heard of this issue?

I worry it is something with the ecu.

 

[LibertyTC]

Above you mention COIL- I thought we were recommending looking at the connector/wires at the INJECTOR.

 

[JasonJ]

So why has no one mentioned checking the spark plug yet? Unless this is a CRD Liberty... that is the first thing to check. When you go to pull the plug to inspect or replace it, you wont be able to help but to inspect the coil and wiring, as well as the injector as you'll be working right in that area.

How many miles on the engine? When were plugs last replaced? Any corrosion on the coil contact spring inside the boot? Water intrusion into the spark plug well? Valve cover gasket leaking oil in there as well?

Test impedance on the coil, local parts stores should have a test chart or test specification for it. Or look at the service manuals PDF that is uploaded to the internet for specs.

After that, I'd start testing the injector and doing a compression test on that cylinder. By now in the diagnostic process you should have found something, or seen some change.

Good luck.

 

[branny]

Thanks for the help. I'll dig into that stuff, maybe even swap parts to another cylinder.

My spark plugs are a couple of years old. They are worth a look.

 

[CactusJacked]

So why has no one mentioned checking the spark plug yet?

Because PO201 means he has a cylinder #1 fuel injector circuit issue. It's either a bad injector, a broken or shorted out wire to the injector, or the PCM is bad. A bad injector is the more common cause of this code.

 

[branny]

Ok, there was nothing obvious on the coils or injector connectors.
The spark plug was very black with soot.
I replaced the spark plug and swapped coils between cylinders 1 and 3.
If the issue moves to cylinder 3 I know it's the coil.
If I get no more trouble, I blame the old plug.
If the issue remains with cylinder 1 I potentially change the injector.

Anything more than that and I start to worry about the ecu I think.

Thanks for the help

 

[JasonJ]

Because PO201 means he has a cylinder #1 fuel injector circuit issue. It's either a bad injector, a broken or shorted out wire to the injector, or the PCM is bad. A bad injector is the more common cause of this code.

True, I misread the DTC, I thought it was P0301, cylinder 1 misfire.

Crap, could even depressurize the fuel system and swap injectors too. I mean, why not check everything?

 

[branny]

I originally had Code 201.
So, i put in a new #1 spark plug and swapped the coils between #1 and #3. I thought this would highlight a bad coil.
Following this, i got the problem and the codes 301 and 201 came up.

It seems my new plug made this issue a little worse...? how odd.

The problem itself is fairly strange, i was going 70mph on the interstate and it started jerking a little. It seemed happy to maintain low cruise throttle, but it would not give me any more to speed up. Could it be throttle related?
When i got to the lights, i could smell fuel...

Any info helpful.

Perhaps next thing to swap is the #1 injector?

 

[CactusJacked]

Because PO201 means he has a cylinder #1 fuel injector circuit issue. It's either a bad injector, a broken or shorted out wire to the injector, or the PCM is bad. A bad injector is the more common cause of this code.

Why you were fiddling with ignition parts to try and fix a fuel injection/fuel supply problem is beyond me. I guess you could next try rotating your tires, you'll get the same results. lol
But seriously, the reason why your #1 spark plug was black and sooty (along with the 201 code) would be because that cylinder is running rich; too much fuel being dumped in by the injector by either a bad/internally leaky/misfiring fuel injector or a circuit issue.
Now you have a cylinder 1 misfire as well. Strange yes, but it could have something to do with what you just did.

 

[CactusJacked]

Now that I think about it more, also getting the 301 code isn't strange. A bad fuel injector can cause a cylinder misfire. Coupled with the 201 code, strongly suggests the injector is the culprit. At least, that would be the first thing to look at.

 

[branny]

Now that I think about it more, also getting the 301 code isn't strange. A bad fuel injector can cause a cylinder misfire. Coupled with the 201 code, strongly suggests the injector is the culprit. At least, that would be the first thing to look at.

Yes. It certainly feels like that's the case.
Do you have a good guide on injector removal and change?

I may just go buy one for $47 rather than doing the whole swap around.

 

[branny]

Ok, i fitted a new injector in cylinder 1.
After a few short trips in succession, nice and hot engine. I got the check engine light and it started refusing any more than minimum throttle.

It is not a 'typical misfire'. The engine is jerking in time, almost like it must be electrical.

Does anybody recommend anything else?

Does the throttle position sensor really make sense here?

 

[ltd02]

Have you checked the wiring and connector to that fuel injector? teeje and LibertyTC already suggested this but I haven't read that you had.

Starting to sound like the ECM could be the culprit. Need to rule everything else out before you go messing with that.

 

[branny]

Thanks, I have only done visual connection checks.
You think I should ring them out?


Also, as this is an intermittent "hot only" problem, it makes wiring checks difficult