Trans 12 Volt Supply Relay Control Circuit
NAME OF CODE173 ($AD) - Transmission 12-Volt Supply Relay Control Circuit
WHEN MONITORED
Continuously with the key on
SET CONDITION
This code is set if the voltage detected on the Transmission Relay Control Circuit at the Powertrain Control Module (PCM) is different than the expected voltage for 3 seconds.
THEORY OF OPERATION
The Transmission Relay is used to supply power to the Torque Converter Clutch (TCC), 3-4 Shift, and Governor Pressure solenoids. When the relay is off, the transmission is in "3rd gear limp-in mode".
TRANSMISSION EFFECTS
The PCM turns off the transmission relay resulting in the transmission going into default mode (3rd gear). The MIL will illuminate.
POSSIBLE CAUSES
- Transmission relay failure
- Open or shorted transmission relay control circuit
- Corroded, damaged, pushed out, miswired, or disconnected connector(s)
- Internal controller failure (PCM)