Buick Century Transmission Code P1811

2000 Buick Century transmission code p1811 max adapt & long shift. P1404 egr valve.

We changed fluid and filter. Ihave the following codes. What do they mean? P1811 max adapt & long shift. P1404 egr p0742 tcc stuck on.

Reply:
Could you tell me if these codes all came at the same time? Have they ever been cleared, and then driven to see which code comes back first. I will wait for your reply and give you some info. Thanks.

VISITOR:
Yes they were all read at the same time..I was told to change the trans,filter as soon as i could and i did.I have not done or read any codes since..I'm not equipped to do so without taking it to a garage.I need to know what i have to get and do..Your welcome for the donation..Jerry.

ANSWER:

Well, the egr code p1404 is for closed position performance. The computer(PCM) does not see the egr go to a fully closed position. 2 possibilities. The egr is bad or full of carbon and cannot close all the way. Remove and cleaning sometimes can help, but not always. There also may be a pcm re-programming for this code. A re-calibration of a false code setting. A re-programming adjusts what the pcm want s to see. Only way to check that is to have the dealer scanner hooked up and check for updates.

The p1811- max adapts and long shifts. The pcm is seeing a longer than normal up shift time, and tries to compensate by raising line pressure. It can only do this to a point. When it can no longer compensate, and the shifts are still too long, this code sets. Several things can cause this. Actual internal transmission component slipping, problem in the trans. Pressure control solenoid or valve body. A Technician would have to hook up a pressure gauge and look at live transmission data to determine this.

The p0742 - tcc stuck on is usually a tcc solenoid or valve body problem. Either a failed solenoid, stuck solenoid because of debre in the valve or valve body. Which brings me back to the p1811. Any debre in the valve body can cause problems with either of these solenoids. If either solenoid has come apart, small pieces of the solenoid would be in the valve body, and cause a problem with other valves.

As with the p1811, worst case is that the trans needs an overhaul. I know that is not what you want to hear, but it is a possibility, especially if the old fluid was burned. This would have to be properly diagnosed by a transmissionTech. Not something that can be fixed in your garage.