12 Battery Was Disconnected

THEORY OF OPERATION:
A battery backed RAM (Random Access Memory) is used to maintain some learner values. When the battery B(+) is disconnected the memory is lost. When the B(+) is restored, this memory loss is detected by the TCM. The code is set and the learned values are initialized to known constants or previously learned from EEPROM (Electronic Erasable Programmable Read Only Memory). This results in the reinitialization of some parameters.

LIMP-IN:
YES

WHEN MONITORED/SET CONDITIONS:
Whenever the key is in the Run/Start position. This code is set whenever the Transmission Control Module (TCM) is disconnected from battery power B(+) or ground. It will also be se during the DRB Quick Battery Disconnect procedure. On some 95 MY vehicles, it will be set during a DRB Quick Learn procedure.

TRANSMISSION EFFECTS:
All model years and calibrations - Loss of trouble code data. Immediate limp-in mods if power is lost while operating the vehicle. Normal operation is resumed if the power is restored during the same key start.

POSSIBLE CAUSES:
- Battery voltage removed from TCM
- TCM disconnected
- Dead Battery Low battery voltage during cranking Quick battery disconnected by DRBIII or MDS Quick learn by DRBIII for some 95 model year vehicles Bad TCM ground circuit