P1810 but Fast Idle

This is on my 2003 Chevy Venture where I had a no crank no start that I ultimately suspected to be security related because of the message center constantly rotating through Battery/Security/Low Fuel. I eventually resolved that issue by replacing the Passkey 3 module, BCM and ultimately the PCM.  Now I am left with occasional P1810 that I believe to be related to fast idle and may not be related to any transmission pressure sensor or solenoid at all. Also, I did not have this hard shifting issue before my van was a no start and no crank after sitting for the winter and I replaced the battery and then battery/security/low fuel....the rebirth of occasional gremlin, this time would not go away.

BEFORE I FINALLY REPLACED THE PCM AND GOT THE VAN TO START AND STAY RUNNING WITH NO BATTERY/SECURITY/LOW FUEL LIGHTS EVER AGAIN...

I did replace Mass Air Flow Sensor. TPS and Engine Coolant Temp Sensor and Oil Pressure Sensor and the CAM Sensor.
No reason to get into why but there was a TPS low voltage circuit A with the old computer and I thought it was worth throwing $15 at.  The problem was not resolved until I got replaced the PCM.  AS for the rest, the MAF Sensor was previously from a salvage yard and I thought I had better replace it.  The others were cheap and I decided ot do them.

Anyhow, I am getting P1810 and I read that it is usually a pressure solenoid inside the transmission. HOWEVER, my van is idling very fast after first start and the shifting to reverse and drive is very hard until the van warms up. There is an occasional hard or slip type shift while driving until the van warms up and then it runs just fine.  I can clear the code and not see another P1810 no matter how many times I stop and start the van until I let it sit long enough to get cold.

This is why I am entering this question into the forum. Can the P1810 be caused by the hard shifting during fast idle? If so should I try replacing the cheap aftermarket TPS with an AC Delco?  Should I look elsewhere?  Should I even be thinking of looking elsewhere before looking into having someone service the transmission. I do not think I want to put the $ into the latter.

Thanks for your time once again.

No offense meant here, but are you sure P1810 is the code you're getting? :huh: Because I can't find it in service info.

P1811 Maximum Adapt/Long Shift, however, is a very common code for the transmission in your Venture. It sets when there's a shift time longer than .65 seconds, and the PCM has maxed out the adaptations to shorten it. Two long shifts in one trip generates the P1811.

wrote:

No offense meant here, but are you sure P1810 is the code you're getting? :huh: Because I can't find it in service info.

P1811 Maximum Adapt/Long Shift, however, is a very common code for the transmission in your Venture. It sets when there's a shift time longer than .65 seconds, and the PCM has maxed out the adaptations to shorten it. Two long shifts in one trip generates the P1811.
 

IIRC this van has a PCM from an earlier model year in it. Just checked and P1810 is a valid code for the '01 MY. Don't have time to compare '01 and '03 transmission wiring diagrams right now.

Bus driver Matt T takes me to school again. :blush: :lol: You're right, it is a code for an '01.

I wonder if the code is the result of the '01 PCM looking for inputs that don't exist on the '03 transmission? Because the '01 diagram shows pressure switches, but the '03 doesn't.

wrote:

Bus driver Matt T takes me to school again. :blush: :lol: You're right, it is a code for an '01.

I wonder if the code is the result of the '01 PCM looking for inputs that don't exist on the '03 transmission? Because the '01 diagram shows pressure switches, but the '03 doesn't.
 

Was just something I remembered from the end of the last thread on this van. It was setting a pre '03 code after the PCM swap.

Pretty sure you've confirmed what I suspected. P1810 is a pressure switch plausibility code............

Attached is the error and you are correct that the computer was the problem.  HOWEVER, I not being a mechanic did not suspect there to be a difference in transmission because both the 2001 computer VIN and my Van VIN...when I research specs, says the transmission is the same. Thus I figured my van might be hard shifting and sometimes slipping because maybe the 2001 computer I used for replacement was looking for a secondary air pump that is not present on my 2003 Venture. THERE WAS A VERY FAST IDLE UNTIL RUNNING TEMPERATURE WAS ACHIEVED.  However, you may be correct and likely are, not only because of your experience, but because my van has a replacement transmission in it that I believe came from a 2005 Pontiac Montana back in 2016.


I did not see this forum entry until after I decided to risk $25 on a PCM from a 2005 Pontiac Montana. I put it in yesterday and it learned my key right off the bat and the van runs like a champ.  IN FACT, I believe my transmission likes this 2005 Montana PCM better than it liked my original PCM for my 2003 Venture. (Sadly the mechanic that did the replacement  job back in 2016 is no longer with us since about 1 month after he replaced the transmission.)  This van runs great right now with no codes  (EDIT...maybe not true..see reply after this entry).  I can run it in drive an no hard shifting, no slipping. I can only hope that I didn't overstress things like my fuel pump and transmission while trying to get the van running with the original computer.  My fans run properly too.  They were not running properly with the original PCM and the 2001 PCM.  Until I put this latest PCM in my van, my coolant fans would not run when the AC was turned on.  I still think there might be an issue here. They are not spinning very fast.  Maybe my high speed fan control or relay is a problem, I'm not sure but both fans are running yet the tempurature drifts pretty high in idle.  This may be the only issue I have to resolve along with passenger side air bag and ABS  but I am not really worried about those.

Attached is the P1810 I was getting. It says 3/6 because the other two errors were for the secondary air pump that did not exist in my van and my scanner repeated all 3 errors twice.  NOT THAT IT MATTERS AT THIS POINT but when I search my vin and the vin of the 2001 PCM for vehicle specs they both show the exact same transmission. I have not searched the vin for the 2005 Pontiac I took this latest PCM from.

So Now I have taken the van on two drives. First one was about 25 miles and second one was around 60 miles. I got a P0036 that I cleared to see if it would come back. I got a P0172 that I cleared to see if it will come back. Maybe I am wrong but I think I am going through an idle relearn with the changed to a 2005 Pontiac Computer.

I wonder how much difference would be in things like the Idle Air Control valve and maybe TPS or other sensors between when the 2001 computer was looking for a Secondary Air Pump that did not exist vs now the 2005 Pontiac Grand AM Computer isn't looking for that anymore. The transmission shifting....I barely feel any shifting at all. That's Amazing to almost scary. I can run through all the gears manually and that seems to work properly.

I am trying look back and see what transmission was put into my van back around 2016. I think it was from a 2005 Pontiac Grand AM.

Does anyone know a site that exists where I can enter VIN numbers to get accurate vehicle specs?
When I compared the VIN of the 2001 PCM to my Van's PCM, the only link I found was Autozone that gave specs showing both vans to have identical transmissions.
I am trying to find the receipt for the transmission that was put in my van back in 2016. I want to look up the VIN of the van that the current PCM came from.
Thanks for your time on this. I appreciate your help and that this forum exist.  I am telling people about your site and your youtube and your teaching whenever in parts
stores and such.

If that transmission number you found is 4T65E it doesn't really mean much. GM change transmission internals over the years without changing the headline transmission number.