Make sure the battery is fully charged. The 12 code has to do with the loss of power from the Battery.
The 55 code has to do with the instrument cluster.
Was the problem present 3 years ago, or is this new?
IT is stuck in limp mode due to inadequate power or a transmission problem. Not all scanners can read for transmission codes. IF the battery is fully charged there should be transmission codes present.
IF not then you need to start checking for a signal loss to the tcm, such as an ignition switch problem that is not sending a signal.
If the problem was not there 3 years ago, I wauld start checking connections and the tcm for any corrosion as time can do that. May need to check for continuity to be sure power is not being halted.
Also an EATX relay can cause a limp in mode with no fault codes.
Tuesday, April 7th, 2009 AT 4:39 AM