Expert: Roland Finston - 11/22/2011

Question
Hello Roland, I have a 2006 PT Cruiser that every now and then will not shift out of limp mode (2nd gear)my son and I removed the battery cable while we were looking under the hood;and we noticed that when we replaced the cable and took it for a test drive it was shifting fine. Then I took it to a dealer and left it with them,and after 2 days they were unable to find anything wrong with the car,and about a day or two later it did the same thing. So once again we removed the battery cable to reset the transmission, I live in a rural area and for me to have a tow truck would cost me an arm and a leg. Any Ideas what this could be???? Thank you for your time.   Laura

Answer
Hi Laura,
Removing the battery supply will cause an erasure of the memory of the transmission controller that contains a coded fault number that says what it thinks is wrong and therefor but it into limp mode, so that is normal behavior. As soon as it 'sees' the problem again, it set the code in the memory and puts the trans in limp mode if the code calls for that response. The limp mode is accomplished by essentially turning off the electrical relay that operates the transmissions electrical parts and its purpose is to avoid any unnecessary damage should the transmission be allowed to continue to operate.
So what you need to know is what is the fault code number. That is typically obtained using a fault code reader the plugs into a socket under the dash next to the steering column. If there is any sort or auto repair shop within driving distance then I would go there and have them do the code readout of the transmission memory. Call first to see if they have a reader that will do that. They shouldn't charge more than about $40 for doing that. If by chance there were a nationwide auto parts store nearby then they often will do the readout for free so call there and ask.
Let me know the 4-digit code number(s) that you find and we can then discuss what it means. Ask the shop what the name of that code is, what they think should be done, and how much it would cost. Then we can compare what they say with what the Chrysler service manual says.
Just on a chance try turning the ignition key:"on-off-on-off-on and leave on" doing that in 4 seconds or less elapsed time. Then watch the mileage reading on the speedometer to see whether it changes to show the 4-digit numbers. On some model is earlier years that did happen, but I con't think it will on the '06 PT. But give it a try.
Roland