Hello, 2005 IS250 has some codes need explaining, please help:

Fault code: DTC0P2127 Throttle/Pedal Position Sensor/Switch E Circuit Low Input (I have a Throttle controller that jacks itself between the foot pedal connection, this might be it)

Fault code: DTC0C1223 ABS Control System Malfunction / ABS Malfunction
Fault code: DTC0C1241 Low Battery Positive Voltage or Abnormally High Battery Positive Voltage / Low battery voltage
Fault code: DTC0C1249 Open Circuit in Stop Light Switch Circuit / Open circuit in stop lamp switch circuit
(Will replacing the ABS Module solve the problem?)

Fault code: DTC0U0121 Lost Communication With Anti-Lock Brake System (ABS) Control Module (Sounds like ABS ECU need replacing?)

 

Take out the throttle controller. Then reset the DTC codes. The ABS codes may not erase. If so you'll need a scan tool with ABS capability to erase these codes.