NATS Anti-Theft Communication Failure
The P1625 code indicates a communication or validation failure between the Engine Control Module (ECM) and the Body Control Module (BCM) or Immobilizer Unit (IMMU) within the Nissan Anti-Theft System (NATS). This code is associated with the SBDS Interactive Codes routine, which verifies the exchange of rolling security codes between modules. If the verification fails, the ECM disables fuel injection and/or engine start to prevent unauthorized operation.
01. Most Common Causes
- Unregistered master key or damaged transponder chip
- Faulty immobilizer antenna (reader ring) around the ignition cylinder
- Open or short circuit in the CAN or K-line communication wire between ECM and BCM/IMMU
- Defective BCM or IMMU
- Low battery voltage or voltage fluctuations during cranking
02. Symptoms You Will Notice
- Engine cranks but does not start
- Security light flashing or staying on
03. Step-by-Step Diagnosis
Check for any related codes in the ECM and BCM.
Inspect the immobilizer antenna ring and its wiring for damage.
Test communication on the CAN bus and K-line between ECM and BCM.
Verify the key transponder is recognized using a compatible scan tool.
Check battery voltage and charging system for stability.
1. Frequently Asked Questions
Is it safe to drive?▼
No, the vehicle may not start or may stall while driving due to the anti-theft system disabling fuel and ignition. It is not safe to drive until the issue is resolved.
How much does it cost to fix?▼
Repair costs typically range from $100 to $600, depending on the cause. A simple key reprogramming may cost $100-$200, while replacing a BCM or ECM can cost $300-$600 or more.