Trouble code P1516 indicates a problem with your Saturn L300's Throttle Actuator Control (TAC) module. A problem with the gas pedal position sensor is a different trouble code (P0121, P0122, P2138). Focus on the actual throttle control unit on the intake manifold. Start with the wiring; make sure everything is connected, the harness is not broken, or pins bent. Then move on to the unit TAC module itself.
Saturn L300 - For OBDII trouble code P1516 check the following:
- Throttle Actuator Control (TAC) module harness is open or shorted
- Throttle Actuator Control (TAC) module circuit has poor electrical connection
- Throttle Actuator Control (TAC) module defective
- Dirty and binding throttle plate (butterfly)
- Defective throttle body (internal mechanism not functioning properly)
Saturn L300 - P0405 indicates Exhaust Gas Recirculation Sensor Circuit Low; meaning there is the possibility of having an EGR system electrical fault rather than a mechanical problem. For OBDII trouble code P0405 check the following:
- Faulty EGR volume control solenoid
- Dirty EGR valve (internal carbon buildup)
- EGR volume control solenoid harness is open or shorted
- EGR volume control solenoid valve circuit poor electrical connection
- Faulty EGR temperature sensor and circuit (applies only if P0401 exists)
