The OBD-II trouble code P0605 is a generic powertrain code that indicates an issue with the Internal Control Module Read Only Memory (ROM).

Land Rover OBD-II Trouble Codes -------------------------------------------------The OBD-II trouble code P0605 is a generic powertrain code that indicates an issue with the Internal Control Module Read Only Memory (ROM). Specifically, it suggests that there is a malfunction in the Engine Control Module (ECM) or Powertrain Control Module (PCM) that relates to the read-only memory, which contains critical software and programming data for the module's operation.

Here are some common causes of the P0605 trouble code:

1. **Faulty ECM/PCM:** The ECM or PCM itself may be malfunctioning or experiencing an internal memory issue related to the ROM. This can occur due to wear and tear, electrical problems, or other factors.

2. **Software or Firmware Issues:** Software or firmware errors within the ECM or PCM can lead to ROM-related problems. These issues may require reprogramming or updating the module's software.

3. **Faulty Wiring or Connectors:** Damaged or corroded wiring, connectors, or pins in the ECM/PCM circuit can lead to communication errors and ROM issues.

4. **Low Battery Voltage:** Low battery voltage or voltage fluctuations can disrupt the ECM or PCM's ROM and trigger a P0605 code. This can happen due to a weak battery, a failing alternator, or poor electrical connections.

To diagnose and address the P0605 code, you may want to follow these steps:

1. **Check Battery Voltage:** Ensure that the vehicle's battery voltage is within the proper range. A weak or failing battery can cause voltage fluctuations that affect the ECM/PCM's ROM. Charge or replace the battery if needed.

2. **Inspect Wiring and Connectors:** Visually inspect the wiring and connectors related to the ECM/PCM. Look for damaged wires, loose connections, or corrosion. Repair or replace any damaged components as necessary.

3. **Clear the Trouble Code:** After addressing battery and wiring issues, use an OBD-II scan tool to clear the P0605 trouble code. Drive the vehicle and monitor for the code's return. If it reappears, further diagnostics may be needed.

4. **Inspect and Test ECM/PCM:** If the problem persists, have the ECM/PCM inspected and tested by a qualified technician. They can check for internal faults and determine if the module needs replacement or reprogramming.

5. **Check for Software Updates:** In some cases, manufacturers release software updates or patches to address ECM/PCM issues. Check with the manufacturer or a qualified technician for any available updates.

Diagnosing and addressing ROM-related issues within the ECM/PCM can be complex and may require specialized equipment and knowledge. If you are unsure about diagnosing or fixing the problem yourself, it is recommended to seek the assistance of a qualified mechanic or a Land Rover dealership. They can perform a comprehensive diagnosis, use specialized tools, and make the necessary repairs to resolve the P0605 trouble code and ensure your Land Rover operates correctly.