CODE 12- RPM SIGNAL
Code 12 is caused by loss of "G" or "NE" signal from distributor to ECU for at least 2 seconds after starter signal is received at ECU. Check distributor and ignition system components. Ensure starter signal (STA) exists at ECU.

CODE 25 - LEAN AIR/FUEL MIXTURE
Probable Causes:

Loose Engine Ground
Open E1 Circuit
Open Injector Circuit
Fuel Line Pressure (Blocked Injector)
Open Or Short In Oxygen Sensor Or Circuit
Ignition System
Coolant Temperature Sensor
Airflow Meter Or Air Intake System (3VZ-FE)
Vacuum Sensor (5S-FE)
ECU

Answered by KHLow2008 (expert)
40,318 answers provided