Hi,

I'm getting a P1810 on a 4L60E. The code error message indicates its a faulty pressure switch. I replaced the pressure switch which fixed the error code for a short time, but it came back after driving it for a short time.

The symptoms are that after the tranny warms up, it will fail to get out of second gear. What else cold be causing it? I noticed the tranmission fluid is a little over the full mark, but after reading some posts on this forumn, it seems that this should not be causing it.

Any thoughts? Help appreciated,

Cheers,
Greg

 

Since you replaced it then its most likely an issue with the harness or plug to the trans (common), That would be my first go to in looking for the issue , However barring that it also could be a VB crossleak .
And also even an issue with vehical ground I once had a car that was setting these codes was the battery to chassis ground/engine was badly corrroded.

 

Recorded the transmission parameters from my scanning software today while dring the car around the block. The "Commanded Gear" parameter never goes past 2 even though I got the speed up to 53 kph. Not sure if the gear change trigger points are tied to the rpms or the speed? Anyway, if anyone can deduce anything from the attached, would appreciate it.

Cheers,
Greg

4L60E params

 

Can you post a pic of the switch that you changed?

 

Also do you actually have 1st gear being commanded or just stuck in 2nd? Can you manually shift to D3 and get 3rd? How dirty was the old switch? Im assuming if it was bad, more unknown debris could be affecting your new switch as well. Just something to consider

 

Ok I see it is starting in first and shifting to second automatically so it is not limp mode as then it would always show 3rd gear.. What I do not see which would be helpful is the manual position which you should be able to see in the data stream also. But No doubt since 3rd is not being commanded it is a sensor or PCM issue and since replacing the manifold presure switch did fix it temporarily Im still betting on a wiring issue but getting the manual position in the data stream would tell you tons and make diagnostics much easier , I assume it can be added though I ma not super familiar with the tuning software you are using, I know I can see it in TunerCat and can add as a parameter on my own car.

 

Sorry, but what you can see is everything my software can show on the tranny.

I had the car in Drive during the test. I did think about doing another test and moving it into 3rd manually, but when I went to do the test, I had another problem with the engine (for which I have started another thread). Its losing oil pressure unexpectly, so I thought not a good idea to drive it until I get this issue fixed.

 

Like I said not familar with the software you are using . Mine can show manual gear position D-R-N-4-3-2-1 But yes I would certainly solve the engine running issue first ,
Hope nothing to bad,

 

Finally got my oil pressure problem fixed. I noticed when I was driving the car to confirm the oil pressure was ok, the tranny was shifting gears ok. It went up the gears to 4th, and then back down as it should. However, when it warmed up, got a P1810 again, and then wouldn't go past 2nd.

Will do some more testing to try to work out what's going on with it. I had a thought regarding the transmission filter. I read there are two types of pan, a deep one and a shallow one. I have the deep one. What would happen if I mistakenly installed the filter for the shallow pan in my tranny ? Would that cause a P1810 ?

 

Not unless it fell out , But that would cause many other issues too. Still think you are dealing with eitehr the manfold switch on the VB or wiring issue with vehicle or trans harness.. You could have an internal presure leak but that would also generally present as other issues if large enough to not be able to compress the little bubble switches in the manifolid. Since seems to only happen hot I would guess a faulty conector and ince you cant see the data on this its gonna be kind of a guess and play game. You have already changed the switch itself you said so i would next check or change the trans internal harness if it were me , Would be much easier to diagnos if you could see in data stream

 

Notice that the manifold pressure switch has small o-rings for each switch. Make sure there is no grime on the VB where the pressure switch mounts. The bolt are tightened to about 8 ft/lbs (sometimes called 96 in/lbs).
Like Frank says, it sounds like a flakey electrical connection either within the trans harness or the trans connector.

 

Tried reseating the transmission plug and Vss plug today. That seems to have fixed it. Its now going up and down the gears like it should. However, I'm still getting the P1810 code.

I will try to reseat the transmission plug again as I could only get fingertips to it today. I need to drop the rear of the tranny so I can get a better grasp on it. BTW, does it just push in or does it have some kind of locking collar (I can't recall whats under the rubber boot?).

 

​​​​​​it has a snap lock when fully in, Be sure and use a screw driver in little square to hold it up and not push it down into the case,

 

Got a good look at the transmission plug and socket today. The plug has some black marks around some of the pins, could be burn marks not sure. The socket was filthy. It was covered in some black gunk right across the bottom. I really don't know what it is or how it got there.

Anyway, cleaned them both up and was confident this would fix my problem with the P1810 error code. No such luck! In fact, it reverted to the previous behaviour - wouldn't change past 2nd. All I can assume is that there are still one or more pins not making proper contact.

Here is what the plug looked like:


Here's a photo of the socket (sorry about the poor focus):


I'm going to try to wiggle the plug around to see if I can get the gear changes to come back again. If so, its likely a problem with a contact in the plug/socket.

 

replace plug end you can buy them on ebay and amazon IMO

 

Removed the plugs from the PCM and tested the wires coming from the tranny. All the signals read correctly (the resistances of the solenoids were within spec and the temperature sensor and TSS were reading correctly as well). I checked the continuity of the wiring from the tranny connector to the PCM plugs for the pressure switch signals and they indicated no open or short circuits.

Next step I dropped the tranny pan and removed the pressure switch. This is what I found:



As you can see, one of the pressure sensors was completely destroyed. Another one was crushed. When removing the bolts, I noticed one was very tight, two were moderately tight and one was relatively loose. I trusted my mechanic to install this as I didn't want to make a mess with transmission fluid all over my garage floor. Usually his work is very good - he certainly had an off day when he did this little job for me!!!!

So I've ordered another pressure sensor - I'll be installing this one myself for sure. (should be 10 ft-lb for all the bolts, correct ?). I ordered a "Rostra" brand pressure switch - anyone had experience with this brand?

 

Looks like you found your issue and yes aprox, The rostra is fine have used many rostra products over the years.

 

That is a bit too tight. The correct torque is 8 ft-lbs, often documented as 96 in-lbs. Same as all the VB bolts in the area. The HF 1/4" torque wrench works fine for this. Or gorilla strength on a nut-driver.

On the "lighter" side, I recall a post where someone misread the "96 in-lbs" as ft-lbs and had the bolts snap. Somehow VB bolts don't like like wheel studs to me.

 

I replaced the pressure switch. Torqued the bolts to 8 ft-lbs as suggested by mrvedit. Took the car for a drive today and it seems to be changing gears properly. Getting 1 thur 4 in drive. Gears are changing smoothly without any issues.

Thanks everyone for your help and suggestions.

 

Thanks for posting an update to say your problem is solved. That is always appreciated, especially by future people who find this thread via a Google search.