2010 GX460 blinking 4LO, Check Engine and Slip lights (1 Viewer)

[TootYa]

Symptoms:

1) So I am having an issue with my 2010 GX460 where the 4LO indicator is blinking, and the check engine light and slip are also on. I have never shifted out of 4HI, so I know for certain it's not in 4LO and hasn't been in many years.

2) When I check my engine codes I got a P0304 - Cylinder 4 Misfire Detected.

3) Idles fine, but when I shift to R or D, it becomes rough.

4) However, if I reset the code, it idles fine and the roughness completely goes away and I can drive it like nothing ever happened. (Until I let it sit, turn it back on and all the lights come back on).

That to me feels like ECM possibly? Maybe bad electrolytic caps?

I can't find any videos on how to get to the GX460's ECM. Is there a good video or documentation available to show me how to do that so I can inspect it? Or is that a super painful procedure? Maybe it's just drop the glove box?

 

[TootYa]

Oof, after some more searching here, I see recommendations to ask on clublexus for this type of question. I will cross-post over there.

 

[HVLA]

Havent shifted into 4lo in years? Why?
Kept up in all your maintenance?

 

[Acrad]

 

[TootYa]

Havent shifted into 4lo in years? Why?
Kept up in all your maintenance?

I meant I haven't needed to use 4LO ever. I take the car in to my mechanic when it's time for an oil change and ask him to review maintenance records and do it by the book, so I would hope he is maintaining it properly, if that's what you are asking? It was dealer maintained until just a couple of years ago when I switched to a much closer mechanic.

 

[tech703]

idk if im dense or what but wouldnt that point to it being cyl 4? try unlpugging the coil for that cylinder and see if anything changes, if it doesnt maybe a new coil?

Edit: of course car would need to be in the air on stands or lift to test the R or D while doing this

 

[TootYa]

idk if im dense or what but wouldnt that point to it being cyl 4? try unlpugging the coil for that cylinder and see if anything changes, if it doesnt maybe a new coil?

Edit: of course car would need to be in the air on stands or lift to test the R or D while doing this

I just figured that since clearing the code causes the car to behave normally that perhaps it's related to the ECM, but I guess I should start from the traditional end of investigating the cylinder. Why does 4LO blink when I have a cylinder issue? Those things seem unrelated to me, other than erratic ECM, but I 100% admit I don't know what I am talking about either.

 

[TootYa]

View attachment 3331142

@Acrad is column #4 a recommended order for diagnosing, or an unordered list of likely culprits?

 

[tech703]

from my limited experience if its a CEL theres always bound to be a few extra lights unless its like evap leak. But i could be wrong, my thought process would just be if the code is saying its a cylinder than it should be that. If that means its something else than thats just nonsense to me

 

[tech703]

i dont get why that list of possible issues doesnt list a bad plug or coil for a misfire lol, i must be on a completely different wavelength

 

[TootYa]

i dont get why that list of possible issues doesnt list a bad plug or coil for a misfire lol, i must be on a completely different wavelength

I would guess "ignition system" includes those items?

 

[r2m]

One of two options:
1) Work down the list yourself, depending upon your time, expertise and equipment you have. It may cost you more if you're needing to purchase replacement parts as you move down the list till you hit upon it.
2) If you can afford it, have your local mechanic chase it down. He may be able to chase it down without having to purchase any parts except what is needed for the actual problem. In the end this may be cheaper and probably faster.

 

[Acrad]

I would guess "ignition system" includes those items?

That is how I would interpret it.

You can pull down the Factory Service Manuals in this thread

GX 460 Manuals

This post will hopefully be a permanent thread along with the "150 Series Pic Thread" thread as a easy to find resources for all types of GX 460 manuals. Suggested manuals/material to post being: Factory Service Manual (FSM) Owner Manuals (for each year) Wiring diagrams Anything that may relate...

forum.ih8mud.com

10-13

ECM failure for engine is really...really rare

 

[TootYa]

That is how I would interpret it.

You can pull down the Factory Service Manuals in this thread

GX 460 Manuals

This post will hopefully be a permanent thread along with the "150 Series Pic Thread" thread as a easy to find resources for all types of GX 460 manuals. Suggested manuals/material to post being: Factory Service Manual (FSM) Owner Manuals (for each year) Wiring diagrams Anything that may relate...

forum.ih8mud.com

10-13

ECM failure for engine is really...really rare

Oh wow, the FSM! Thank you!

Okay, I will see how bad it is to get to the #4 coil and any other coil I can switch to see if the problem follows. And I will give up on the idea of the ECM. If it's difficult to get to #4 and any other coil then I will give up and take it to a mechanic. But I do like to learn and dive in when I am able to, so thanks for the FSM!

 

[Acrad]

Another FSM version as well for 10-13.

Large zip archive you will want to extract on a desktop computer or laptop

 

[Acrad]

Proceed like changing spark plugs

 

[HVLA]

I meant I haven't needed to use 4LO ever. I take the car in to my mechanic when it's time for an oil change and ask him to review maintenance records and do it by the book, so I would hope he is maintaining it properly, if that's what you are asking? It was dealer maintained until just a couple of years ago when I switched to a much closer mechanic.

Could be because i come from a gx470 background, but I use 4lo at least once a month to make sure it stays working. Same with the center diff lock. Use it or lose it they always say right?

 

[tech703]

Proceed like changing spark plugs

number 4 seems to be one the easier ones to get to but maybeoove complicated to try to run by unplugging because i had to remove my whole airbox to get on that side when i changed plugs

 

[aztoytec]

Start w the basics! Pull #4 spark plug. Check for carbon tracking on the plug.

 

[BigSwede]

Misfire codes can be caused by many things, even stuff like vacuum leaks in the intake.

Honestly, the FIRST thing I would check is your alternator. Low voltage can cause many weird codes.