Fault code P1600 – a step-by-step guide to diagnosing and fixing it

Error code P1600 is displayed and the check engine light is on - what does this mean?

The DTC P1600 is a manufacturer-specific fault code that mainly occurs in Nissan vehicles and indicates a problem with the communication between the PCM (Powertrain Control Module) and other control units. The OBD system detects an interruption or fault in the internal ECU communication. With other manufacturers, this code can have different meanings, which is why a vehicle-specific diagnosis is required.

What causes can this error code have?

• Defective PCM (Powertrain Control Module)
• Broken or damaged cable connections to the control unit
• Corroded or loose plug connections on the PCM
• Power supply problems to the control unit
• Defective fuses in the PCM circuit
• Software errors or corrupt control unit data
• Electromagnetic interference
• Damaged CAN bus cables
• Faulty ground connections

What symptoms occur in parallel with fault code P1600?

• Starting problems: The vehicle is difficult or impossible to start
• Check engine light: Permanent illumination of the check engine light
• Loss of power: Reduced engine power and poor acceleration
• Irregular idling: Engine runs unevenly or stutters at idle speed
• Communication error: OBD scanner cannot establish a connection to the vehicle
• Transmission shifting problems: Automatic transmission shifts irregularly or gets stuck in a gear

How can I fix the problem with error code P1600?

• Repairing trouble code P1600 requires systematic diagnosis and targeted measures.
• Carry out a PCM reset: Disconnect the battery for 15 minutes, allow all capacitors to discharge and reset the control unit, then delete the fault code and carry out a test drive
• Check and repair cable connections: Visually inspect all cable harnesses to the PCM, replace damaged or corroded cables and clean plug connections with contact spray
• Check the power supply: Test battery voltage and charging system, replace defective fuses and measure voltage drop at PCM connections
• Update PCM software: Have software update or reprogramming of the control unit carried out at authorized workshops
• Replace the control unit: In the event of irreparable PCM damage, replace the entire control unit and have it programmed to the vehicle
• Diagnose the CAN bus system: Check communication lines between control units and repair defective bus connections