Hello all I bought my second disco the other day for a winter project. I might have bit off more than I can chew but anyways here is my first issue.
Flashing m and s light plus P0722 code.
I have read all the post check battery and alternator and grounds. I have done that also opened up xyz switch it looked brand new.
Car will usually start up without codes. After driving, it shifts from first gear into limp mode at about 20 mph. Lights start flashing.
Now I have searched and searched and seems like a lot of people have had this problem. I cannot find too many people who have actually fixed it other than a dirty ground. I was wondering if anybody with this problem and fixed it list what they did to fix it. Any help would be great.

 

Forgot to note the truck has 121000 miles.

 

In general OBD2 terms, a P0722 is a code related to the output speed sensor on the transmission.

however, the Disco II shop manual indicates that code relates to the torque converter slipping.
see here: Land Rover Workshop Manuals > Discovery II > AUTOMATIC GEARBOX - ZF4HP22 - 24 > DESCRIPTION AND OPERATION > Page 728

have you checked the fluid level/quality?

 

I forgot to mention the guy before me changed tranny fluid. He could not figure it out either. Also performed the tourqe converter test where you keep your foot on the brake and floor it. The rpms stayed around 2200.

 

My gut feeling is try hat it has to be electrical. But who knows. Any fuses I should check or what about the transmission tcm. Open to any suggestions.

 

This is the second P0722 in the last two weeks where someone hoped the problem would be electrical. On what basis do you choose to ignore what the trans diagnostic system is telling you?

 

I'm not sure what the diagnostic system is telling me. That's why I'm on here. Do you think it is the transmission speed sensor or is tranny shot. Idk.

 

If you pull the transmission output sensor you can test it 292/358 OHMS anything within that range is acceptable. My experience with my truck, I did pulled the sensor and tested and had the same issue, changed the fluid and filter, more likely it was the torque converter but I am not risking so I am in the process of swapping the slush box. By the way, I did everything that is the "easy" stuff, grounds, fuses, sensor, xyz switch and nothing solved this particular code.

 

Your S&M lights are flashing, eh? Perhaps your Rover's trying to tell you something.

 

From RAVE --- P0722 Torque converter slipping

If I saw my truck was overheating I wouldn't change the spark plugs.