Cirrus 1999 LXi Codes P0700, P0720, P0731

It sounds like you need a new output transmission speed sensor, a common replacement item. The part costs about $30 and you can replace it yourself if you can get under the car. I don't have a Cirrus manual, so I can't tell you anymore about the replacement. The part should be widely available at any dealer and you might want to consider replacing the input transmission speed sensor (separate part #) while you're at it.

P0700 - generic transmission problem code. If you can get codes on your odometer, this may be the only one you see. P0720 - output speed sensor as you noted. Even without this specific code, the combination of limp mode and speedometer not working gives a fairly good idea your output sensor is shot. P0731 - First gear incorrect ratio. Most likely related to output sensor failure and set when the car initially shifted into first gear without a working sensor.

These codes may set the MIL (check engine) light themselves, (without manual I can't tell you for sure), so fix them first - replace that sensor. The low fuel may be set by mileage, which is hard to compute without speed (odometer).

All in all, you should be pretty lucky- these sensors are not a big deal.

PLEASE report back what you find. Thanks!

Greg, good advice. I have a 99 Cirrus and had an input sensor fail awhile back. I replaced both sensors at the same time, very simple job. The output sensor can be done from under the front drivers side and the input sensor was easier to get at by removing the hold down screws for the transmission control module and moving it up and out of the way. The input sensor is located between the cooling lines. A 1" open end wrench worked well on the output sensor and a 1" deep socket worked well on the input. Good luck! Lou G

Thank you Greg for the information.

The old sensor was with a lot of metal on it, which I cleaned and put it back. Car was still hot and it looked like it should be OK -shifted all gears, speedometer was working. On the next day morning, on cold start, the sensor wasn't working again, so I went to the dealer. On my way back, after 20 km driving, suddenly sensor started to work again and instead of driving with 3000 rpm in 2nd gear it shifts all gears, as usual. Strange, huh. Anyway, I replaced the sensor and hopefully that will fix this trouble in the system. It cost me $44 CAD from the Chrysler dealer. Now it works good, but Computer is still in training period - I took out the battery (-) end and that reseted the memory and erased error messages which were stored there. Next week I'll have a long trip and after that I'll post an update on this topic.

Thank you Lou for this easy way of access to the output sensor. Unfortunately I found it myself after I followed instructions from the Chrysler's book (on that time this web site wasan't updated yet with your message), which means:

-remove Air Filter

-remove Transmission module

-remove the Computer After that, actually there was no access from the top for the Output sensor. Cool.

So after I saw the location of the sensor, I removed the battery cover and with the wheels turned for right turn I've got full access to the sensor. Actually instead of 90-100 minutes working from the top (and asking yourself "well, after I put this Computer back..."), you can remove the battery cover under the front right fender for 2-3 minutes, change the sensor, close and finish in less than 10 minutes. And you can do that on your parking spot.

Now I have to get the right tool for the input sensor, just in case.

All the best to you guys, Mitko

Cool! I'm glad it worked out.

Update: after 1000 km with the new Otput Speed Sensor everything looks and works fine :)

Excellent. Glad everything worked out and thanks for posting the followup!