Electronic key-immobiliser system fault (Fiat, Alpha Romeo, Audi, Nissan)

What does U1600 mean?

U1600 stands for Electronic key-immobiliser system fault (Fiat, Alpha Romeo, Audi, Nissan). Two or more of the car's computer modules are not communicating properly over the vehicle network (CAN bus).

Network codes cover the communication between the car's computer modules. When the car's computer sees a reading outside its normal range, it stores this code and may turn on a warning light on the dashboard.

Common causes

• Low or weak battery
• Damaged network wiring or connector
• A module that has lost power or failed
• Aftermarket accessories interfering with the network

What to do

1. Read all stored and pending codes with a scanner. Several codes together often point to one cause.
2. Note the freeze frame data (speed, temperature, load) recorded when the code was set.
3. Inspect the wiring and connectors of the part named in the code for damage, corrosion or looseness.
4. Fix the most likely and cheapest cause first, then clear the code and drive to see if it comes back.

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Frequently asked questions

What does U1600 mean?

U1600 means “Electronic key-immobiliser system fault (Fiat, Alpha Romeo, Audi, Nissan)”. It belongs to the network communication group: Two or more of the car's computer modules are not communicating properly over the vehicle network (CAN bus).

Is it safe to drive with U1600?

You can usually drive carefully for a short time, but fix it soon to avoid further damage or higher fuel use.

How do I clear U1600?

Fix the cause, then clear the code with an OBD2 scanner or app. If the fault is still there, the code will come back.

Related codes

• U1417Implausible Left Wheel Distance Signal (Dodge, Chrysler, Jeep)
• U1418Implausible Left Wheel Distance Signal Received (Chrysler, Dodge, Jeep)
• U1430SCP (J1850) Invalid or Missing Data for Function Read Fuel System
• U1451SCP (J1850) Invalid or Missing Data for Function Read Audible Warnings /Anti-Theft Module
• U1612SCP (J1850) Lack of Acknowledgment for Primary Id
• U1736SCP (J1850) Lack of Acknowledgment for Telltales
• U1750SCP (J1850) Lack of Acknowledgment for Audible Warnings
• U1794SCP (J1850) Lack of Acknowledgment for Mirrors

Code meanings can vary by manufacturer. This page is general guidance, not a repair manual. Always confirm the cause before replacing parts.