P1811 - Maximum Adapt and Long Shift Mode Chevy, Pontiac, Saturn, and Buick Front Wheel Drive Vehicles

The P1811 code is one of the most common codes for transmissions in 1997-on GM front wheel drive vehicles. Symptoms of this code include a check engine light illuminated and harsh shifting. Cycling the key on and off may cure the harsh shifting until the criteria for the code is met once more. We are going to cover what causes the code to set and repair options.

Code Criteria

If a shift into any gear other than reverse and forward engagements takes longer than 0.65 seconds to complete, code P1811 will set. The Powertrain Control Module will then command maximum line pressure inside of the transmission, resulting in harsh shifting. The PCM will also command the check engine light or service engine soon light to be illuminated when P1811 is set. Basically, the PCM is sensing a slip, and is increasing line pressure to maximum in order to prevent the transmission from hurting itself further.

Repair Options

In 2002, GM release a technical bulletin for the P1811 code.  See the bulletin by clicking this link http://bit.ly/P1811_Bulletin.  The bulletin states that a mechanical problem in the Pressure Control (PC) solenoid, contamination in the valve body, or incorrect fluid level can cause the P1811 to set.  Those problems could definitely cause a P1811, but what they failed to mention in the bulletin is, what exactly is the PCM looking for when setting P1811.  It's looking for a slip of 0.65 seconds or longer to set the code.  See http://bit.ly/P1811_Diag_Tree.  So it's not as cut and dry as the bulletin makes it to be.  A burnt clutch pack, stripped overdrive clutch hub, worn accumulators, worn valving especially the actuator feed limit valve, and just high mileage can all cause this code to rear its ugly head.  All of which would require transmission disassembly to repair.  Now I'm not saying that P1811 is going to require a major transmission overhaul every time a vehicle comes into the shop with the code.  I'm saying that it is not always going to be as simple as just changing out a solenoid.

How to Know if a Solenoid will Repair the Problem

It is impossible to know for sure what the internal shape of a transmission is while the transmission is still in the car.  The first thing to check is the transmission fluid.  If the fluid level is low, add automatic transmission fluid (ATF) until full.  Remember that transmission fluid needs to be checked while the engine is warm and running with the shifter in the Park position.  After the fluid level is OK, drive the vehicle to your nearest People's Transmission certified shop to have it checked.  If the fluid level was low, there is a leak somewhere that has to be repaired.  The shop will then test drive the vehicle while monitoring data on a scanner that is communication with your vehicle's PCM.  After that, the shop will most likely recommend a pan drop to see if any contamination is being produced inside of the transmission.  If contamination in the form of clutch material or metal is present, then a solenoid replacement will be a waste of money.  If the pan is clean, fluid is in decent shape, and the mileage is below 80,000 miles or so, then maybe a solenoid will fix the problem.  The thing to remember is, if the shop recommends a solenoid, then they are looking out for your best interests.  It still may not fix the problem, but from what they have seen during their checkout, a solenoid replacement is worth the gamble.  If the shop recommends a transmission overhaul, ask them what they found that makes them think that is the only option.  Don't like what they tell you?  Then call The Transmission Guy at Peoples Transmission. 1-888-415-2098

Toyota Corolla and Matrix Recall

I just recently received a call from a customer in Dallas, Texas.  She was concerned with a letter she received in the mail from Toyota about her 2007 Toyota Corolla.  The letter was informing her that a safety recall is requiring the vehicle's Engine Control Module (ECM) to be replaced.  The ECM's have a defect and could cause the engine to suddenly stall while driving. (Click on this link to see a copy of the letter: http://bit.ly/Corolla_Recall)  Her main concern was, approximately one year before she received this notice, the ECM was replaced by a local garage for a P2716 (Pressure Control Solenoid D Circuit) Code.

Her main questions were:

1. Does the ECM that was installed a year prior still have a problem?

2. She paid over $1,000 to have the ECM installed last year.  How can she be compensated for that repair that is now covered under this recall?

Two valid questions, especially since the ECM was replaced based on a bulletin that Toyota released in September of 2007 for the P2716 code. (Click on this link to see a copy of the factory bulletin: http://bit.ly/P2716_Toyota_Bulletin) 

To answer question 1, I don't know yet.  The only way to know if an updated ECM was installed is to see the actual factory recall notice the Toyota technicians have.  Being the recall is so new, the factory bulletin is not yet available to the aftermarket.  I'm going to set out some feelers to see if I can get a hold of it.  On that bulletin, there should be some part numbers that will tell the technician if the existing ECM is one of the effected models.

Question number 2, the following is a copy from the factory letter:

6. Is the repair covered by warranty?  Will I have to pay any money out of pocket for this repair?

This repair will be performed at no charge to the customer. Owners who have previously paid for replacement of the ECM to address this specific condition should refer to their owner letter for reimbursement consideration instructions.

Key words here: "reimbursement consideration".  Only time will tell how Toyota is going to deal with this. 

Here's another twist: The 2005-2008 Pontiac Vibes were built by Toyota and have the same drivetrain as the Corolla and Matrix.  DetNews.com reports Toyota recalling the Vibes for the same problem with stalling.  These vehicles also had the same problem with the ECM's causing the P2716 code, but Pontiac never released a technical bulletin for the issue.  Being there was only 161,754 Vibes built with the issue compared with over 1.3 million Corollas and Matrix vehicles, GM just didn't see it as a big enough issue.

Please comment the blog or contact me at peoplestransmission@gmail.com if you have any incite on this issue.

Customer Satisfaction

This was copied from an email that a customer sent us last week:

Roger,

My name is Ron Becker and you fixed my 1995 Saturn a few weeks ago. You replaced the torque converter clutch. I was very pleased with the quality of service that you provided and just wanted to let you know I wrote a glowing review of your business and posted it to two business search websites. They are "Yelp" and "Insider Pages". Thanks for taking care of me. We are always quick to criticize someone or a business if we don't think we were treated fairly. I feel it's just as important to complement and praise a business if they did a good job so that's what I did.

Ron Becker


That says it all, right?

We appreciate the praise Ron.

How Transmissions Work

This is a great five minute breakdown on how a transmission works.  The transmission shown in the clip is called a 4T45E.  The 4T45E comes in several, light duty GM and Saturn, front wheel drive passenger cars. 

The factory assembly of the unit as seen here, is the only time that the transmission will be new.  Even if the transmission fails under warranty, the dealerships will either repair the existing transmission in the vehicle, or swap it out with a factory remanufactured transmission.  Remanufactured transmissions, commonly called remans, are built just as they would be in a Peoples Transmission Certified shop.  The transmission is removed from the vehicle, dismantled completely (even more than what this video shows), damaged or worn parts are replaced with new, rebuilt, or used parts, cleaned, then reassembled. 

Payless Transmission and Clutch are Peoples Transmission Certified

What is a Peoples Transmission Certified Shop?


All People’s Transmission certified shops go through an extensive pre-screening before certification.

What is a pre-screening?

A pre-screening checks the credibility of the shop on three different levels:

1. Technical competence

• All People’s Transmission certified shops must have at least one technician that is certified through a notable technical organization

2. Tooling

• Today’s modern cars require special tooling to not only perform the repairs, but to accurately diagnose the problem the first time. People’s Transmission checks to make sure the shop is up to date with their special equipment.

3. Reputation

• All People’s Transmission certified shop’s reputations are checked at a local and state level. We check for any complaints related to dishonesty with local organizations like the Better Business Bureau, all the way up to the state level through the Department of Consumer Affairs. Any unresolved issues with the shop will not only not allow certification through People’s Transmission, but any existing People’s Transmission certified shops will have their certifications revoked if any unresolved problems are reported.

Once a shop passes the pre-screening process, they are then eligible to become a People’s Transmission certified shop.

Payless Transmission and Clutch

Payless Transmission and Clutch has been owned and operated by Roger Rodriguez since 1992. They have been at their current location since 2002 after moving from the North Fresno location. Roger is a master certified ASE Technician with an emphasis on transmission and electrical repairs, and works as the shop manager and head rebuilder/diagnostician.