Battery and Ignition (Hard-Wired)

BATTERY
A fused, direct battery feed to the TCM is used for continuous power. The battery feed is spliced and also fed to the contact side of the Transmission Control Relay. On vehicles with an original TCM, built before 1995, if the TCM loses battery voltage for a period of time, it may lose the adaptive memory. Transaxle characteristics may be relearned by performing the quick learn or road test procedures. If battery power is lost to the TCM on vehicles built before 1995 but updated per TSB 18-24-95 (or vehicles built after 1995), then all adaptive learn values will be retained in memory; therefore, a quick learn or road test is not necessary.

IGNITION
When the ignition switch is turned to the OFF (column un-lock), the RUN (ON), or the START (CRANK) positions, the TCM is activated and looks at incoming voltage. If the voltage is above approximately 26 volts or below 8 volts, the TCM automatically powers down which results in limp-in symptoms.