High RPM at highway speed

Hi John,

We need to start with if there are codes or not. This will really limit this down. Do you have a scan tool to pull codes? If so, let me know what they are.

Also, the most likely cause of this is a vehicle speed sensor is not reading correctly causing the vehicle to not command overdrive.

If it is not a speed sensor then there could be other sensors causing this issue. However, the fact that all other gears seem to operate, this points to a control module issue. Not to condemn the PCM but more then likely the PCM is being given bad information.

I have included the diagrams that contribute to shift patterns. If you have a scan tool then we need to monitor all these inputs and look for something that is not reading properly.

Let me know if you don't have a scan tool because that will complicate things in trying to diagnose this. If you don't have one then a parts store can pull codes so let's start there. Thanks

This code is for a rocker arm oil pressure switch. This could cause some shifting issues because the PCM is getting faulty info and basically, it puts the vehicle into a "protection" mode. I would address it and then retest the shifting of the vehicle. Especially, if the vehicle seems to be shifting properly now, this should be taken care of and then see if the other issues come back.

Also, if there are more codes, that would help. However, if this is your only one and after it is repaired the vehicle still has an issue, you will want to monitor the commanded gear vs actual gear. You may see it is commanding overdrive and it is not entering then we can look at an application chart to see what solenoids are involved.