P1614 – Chain of IMMU-KEY (Nissan, Infiniti)

By Brian Jones (Contact Me)
Last Updated 2019-02-22

Manufacturer Specific Definitions for P1614

What Does Code P1614 Mean?

SPECIAL NOTES: Although this guide will deal with code P1614- “Chain of IMMU-KEY”, as it pertains to Nissan and Infiniti applications, be aware that some sources also list code P1614 as “Immobilizer control module/module coding plug communication – no signal.”  And while Nissan’s definition is the most common, other makes may have different definitions of P1614, and this guide will not apply.

Typically this code is triggered because a damaged or unregistered key was used in an attempt to start the engine. It signifies that the IMMU cannot read the key ID signal. In other instances, it means something more severe is wrong with the immobilizer or ECM itself.

What are the common causes of code P1614?

When an unregistered key is used at least five times consecutively, the immobilizer causes the system to lock. This stops you from being able to start the vehicle at all. It also triggers this code to let you know about the problem.

The Nissan Anti-Theft System and Infiniti Vehicle Immobilizer System both have this immobilizer function. It consists of the following components:

• NATS ignition key
• Body control module (either the IMMU or BCM)
• NATS antenna amp (found in the ignition key cylinder)
• Security indicator lamp
• Engine Control Module (ECM)

The immobilizer is fitted into the automobile to prevent theft. It’s an electronic device that cuts off the engine when the wrong key is present. This stop thieves from hot-wiring a car after they’ve broken in.

The microcircuit in the correct key gets activated by a small electromagnetic field that provides current flow to the key body. This turns around and broadcasts a binary code that’s unique to your system. This gets read by the ECM of your car. Once the ECM determines that you have the appropriate coded key, the ECM turns around and activates your fuel-injection system so the vehicle can start.

If you are using the appropriate key and getting a P1614 code, it’s likely either a faulty immobilizer unit or ECM causing the trouble instead.

What are the symptoms of code P1614?

• Your engine won’t start.
• The Check Engine or Service Engine Soon light will be on.

How do you troubleshoot code P1614?

• If you are using the wrong key, you will want to start by getting the right one for the ignition.
• If you have the right key, but it appears to be damaged, you need to get another one from the dealer.
• When the immobilizer light doesn’t come on, you want to check for a blown fuse.
• Remove the steering column cover to disconnect the connector from the immobilizer control unit receiver.
• Check for voltage between this connector and the body ground to determine if there is a problem with the immobilizer.
• Then, check for voltage between the terminal and body ground with the ignition switch on to determine if there is a problem with the immobilizer.
• To determine if there’s a problem with the ECU, you need specialized equipment that inspects and checks the condition of this component.

Codes Related to P1614

• P1610: Ignition key/engine control module (ECM) – malfunction
• P1615: Nissan and Infiniti both use this code for the same problem.
• P1570: Engine start blocked by immobilizer.
• P0606: ECM processor failure

If either the P1570 or P0606 show, it’s unlikely that it’s simply an issue with your key or more possible that you have trouble with your immobilizer or ECM itself.

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