Your battery has nothing to do with these codes. Your vehicles computers have detected a malfunction or failure in the system. This triggers these codes and sets your check engine light. Below I have listed the code meanings and some repair solutions.
P1126 - Throttle Position (Narrow Range) Sensor Circuit Malfunction.
Power supply for the throttle control motor is provided to the ECM via throttle control motor relay. The throttle control motor relay is ON/OFF controlled by the ECM. When the ignition switch is turned ON, the ECM sends an ON signal to throttle control motor relay and battery voltage is provided to the ECM. When the ignition switch is turned OFF, the ECM sends an OFF signal to throttle control motor relay and battery voltage is not provided to the ECM.
Possible Causes For P1126:
- Harness or connectors (Throttle control motor relay circuit is open)
- Throttle control motor relay
P0325 - Knock Sensor Circuit Malfunction
The knock sensor is attached to the cylinder block. It senses engine
knocking using a piezoelectric element. A knocking vibration from the
cylinder block is sensed as vibrational pressure. This pressure is
converted into a voltage signal and sent to the Powertrain Control
Module (PCM) or Electronic Control Module (ECM).
Possible Causes For P0325:
- Knock sensor circuit short to ground.
- Knock sensor circuit short to power.
- Knock sensor circuit open.
- Damaged knock sensor.
- Damaged PCM or ECM
- Repair or resecure harness or connector
- Replace knock sensor Bank 1 (Bank 1 if applicable)
- Replace PCM or ECM
The P0325 DTC is a very common problem with Nissan vehicles.
On most Nissan vehicles the knock sensor is located on top of the engine block.