P1701, P1702, P1703, P1704, P1705, P1706, P1707, P1708 Transfer Box Line Fault

Land Rover OBD-II Trouble Codes -------------------------------------------------The diagnostic trouble codes (DTCs) P1701 through P1708 all indicate faults related to the transfer case, specifically mentioning a "Transfer Box Line Fault." These codes suggest issues with the communication or signal lines associated with the transfer case control system.

Here's a breakdown of each code:

1. **P1701 - Transfer Box Control Module Line:**

   - This code indicates a fault in the communication line between the Transfer Box Control Module and other related modules or components.

2. **P1702 - Transfer Box Control Module Line Low:**

   - P1702 points to a low voltage condition on the communication line between the Transfer Box Control Module and other modules.

3. **P1703 - Transfer Box Control Module Line High:**

   - This code indicates a high voltage condition on the communication line between the Transfer Box Control Module and other modules.

4. **P1704 - Transfer Box Control Module Request for MIL Illumination:**

   - P1704 suggests that the Transfer Box Control Module has requested the illumination of the Malfunction Indicator Lamp (MIL or Check Engine Light).

5. **P1705 - Transfer Box Control Module Request for ABS/ASR Light On:**

   - P1705 indicates that the Transfer Box Control Module has requested the illumination of the ABS/ASR (Anti-lock Braking System/Acceleration Slip Regulation) warning light.

6. **P1706 - Transfer Box Control Module Request for Brake Light On:**

   - P1706 suggests that the Transfer Box Control Module has requested the illumination of the brake warning light.

7. **P1707 - Transfer Box Control Module Request for Engine RPM Reduction:**

   - This code indicates that the Transfer Box Control Module has requested a reduction in engine RPM.

8. **P1708 - Transfer Box Control Module Request for Gearbox Lock:**

   - P1708 suggests that the Transfer Box Control Module has requested the locking of the gearbox.

### Possible Causes:

1. **Faulty Transfer Box Control Module:** Issues with the Transfer Box Control Module, which may include internal faults affecting communication.

2. **Wiring Issues:** Problems with the wiring or connectors associated with the communication lines between the Transfer Box Control Module and other modules.

3. **Poor Connection or Terminal Issues:** Loose connections, corrosion, or damage to the connectors or terminals related to the communication lines.

4. **Voltage Issues:** Irregularities in voltage levels on the communication lines, leading to low or high voltage conditions.

5. **Module Communication Issues:** Problems with communication between various modules within the vehicle's network.

### Diagnostic Steps:

1. **Inspect Transfer Box Control Module:** Test the Transfer Box Control Module for proper operation using a scan tool or specialized diagnostic equipment. If faulty, it may need replacement.

2. **Check Wiring and Connectors:** Inspect the wiring and connectors associated with the communication lines. Look for any signs of damage, corrosion, or loose connections.

3. **Verify Voltage Levels:** Check the voltage levels on the communication lines to ensure they are within the specified range.

4. **Perform Communication Tests:** Use diagnostic tools to perform communication tests between the Transfer Box Control Module and other related modules.

5. **Check for Additional Faults:** Use a scan tool to check for additional trouble codes in other modules that may be related to the transfer case or communication issues.

6. **Clear Codes:** After addressing any identified issues, clear the trouble codes and monitor the system for recurrence.

7. **Consider Professional Assistance:** If you are unsure about diagnosing or addressing these issues yourself, or if the faults persist, it's advisable to consult with a qualified mechanic or technician.

Addressing the root cause of the Transfer Box Line Fault codes is crucial to ensure proper operation of the transfer case and related systems. If in doubt or if the faults persist, seeking professional assistance is recommended for a thorough diagnosis and effective repair.