P1668 Land Rover Code - Engine Anti-Theft Signal Circuit High
Quick Answer
The Body Control Unit (BCU) uses the driver's door key lock and unlock switches to activate and deactivate the security system. Common causes include Faulty Body Control Unit (BCU), Body Control Unit harness is open or shorted, Body Control Unit circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P1668 Land Rover indicates Engine Anti-Theft Signal Circuit High.
- Common causes
- Common causes include Faulty Body Control Unit (BCU), Body Control Unit harness is open or shorted, Body Control Unit circuit poor electrical connection.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code P1668 Land Rover Description
For immobilization, the BCU disables the starter motor relay. When the engine is cranking, the Engine Control Module (ECM) looks for a coded signal from the BCU. If the signal is not received within one second of cranking, the fuel supply to the engine is stopped and the injectors are disabled. This also prevents unburnt fuel from entering the catalyst.
If the BCU is disconnected, the engine starter motor will remain isolated by the starter motor relay and the ECM will remain immobilized. The main wiring for the system is contained within the main harness, which is relatively inaccessible, so preventing intruders from disabling the system by cutting the wires for the immobilization system. Once the immobilizer has been activated, the destruction of the trigger device or the wiring to it will not disarm the system.
The RF transmitter communicates to the BCU via the RF receiver using a 70 bit code. Pressing the unlock button on the transmitter will re-mobilize the vehicle. The RF transponder is integrated into the metal key assembly, inserting the key into the ignition switch will induce a signal in the exciter coil to re-mobilize the vehicle.
If Diagnostic Trouble Code (DTC) P1668 is set, there is an engine anti-theft signal circuit high voltage caused by a serial link open circuit.
What are the Possible Causes of the DTC P1668 Land Rover?
- Faulty Body Control Unit (BCU)
- Body Control Unit harness is open or shorted
- Body Control Unit circuit poor electrical connection
How to Fix the DTC P1668 Land Rover?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P1668 Land Rover code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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Frequently Asked Questions about P1668 Land Rover Code
1. What are the common symptoms of OBDII code P1668 in a Land Rover related to the Engine Anti-Theft Signal Circuit High?
- Common symptoms include difficulty starting the vehicle, engine stalling, and the inability to turn off the alarm system.
2. What could cause the Engine Anti-Theft Signal Circuit High code P1668 in a Land Rover?
- Possible causes include a faulty immobilizer system, damaged wiring in the anti-theft circuit, or a malfunctioning key fob.
3. How can I diagnose the Engine Anti-Theft Signal Circuit High code P1668 in my Land Rover?
- Diagnosis typically involves using an OBDII scanner to retrieve the specific code, inspecting the anti-theft system components, and checking for any visible wiring issues.
4. Can a DIY enthusiast repair the Engine Anti-Theft Signal Circuit High code P1668 in a Land Rover?
- While some basic checks like inspecting wiring connections can be done by DIYers, diagnosing and repairing complex issues with the anti-theft system may require professional help.
5. Are there any simple troubleshooting steps I can take for the P1668 code in my Land Rover?
- You can try resetting the anti-theft system by disconnecting the battery for a few minutes and reconnecting it. If the code persists, further diagnosis may be necessary.
6. Is it safe to continue driving my Land Rover with the P1668 code related to the Engine Anti-Theft Signal Circuit High?
- It is not recommended to drive the vehicle with this code present, as it can lead to potential security issues and may cause further damage to the anti-theft system.
7. How much does it typically cost to repair the Engine Anti-Theft Signal Circuit High code P1668 in a Land Rover?
- Repair costs can vary depending on the specific issue causing the code, but they may range from a hundred to a few hundred dollars, including parts and labor.
8. Can a faulty key fob trigger the P1668 code in a Land Rover?
- Yes, a malfunctioning key fob can disrupt the anti-theft system and potentially trigger the Engine Anti-Theft Signal Circuit High code P1668.
9. Will resetting the OBDII codes make the P1668 code disappear permanently in a Land Rover?
- Resetting the codes may temporarily clear the P1668 code, but if the underlying issue with the Engine Anti-Theft Signal Circuit High is not addressed, the code is likely to reappear.
10. How long does it typically take to diagnose and repair the P1668 code related to the Engine Anti-Theft Signal Circuit High in a Land Rover?
- The diagnosis and repair process can vary based on the complexity of the issue and the availability of parts. It may take a few hours to a day to complete the repair.
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