Fault code P0602 – a step-by-step guide to diagnosing and fixing it

Error code P0602 is displayed and the check engine light is on - what does this mean?

The DTC P0602 indicates a programming error in the engine control unit (ECM/PCM) that the OBD system has detected. This error code indicates damaged or corrupt software in the control unit, which prevents the vehicle from functioning properly. For various manufacturers, this code may be referred to as "Control Module Programming Error" or "ECM Programming Error".

What can cause this error code?

• Corrupt software in the engine control unit
• Interrupted programming process of the ECM/PCM
• Defective or damaged engine control unit
• Voltage drop during programming
• Faulty flash memory in the control unit
• Incompatible software version
• Damaged internal connections in the ECM
• Electromagnetic interference during programming

Which symptoms occur in parallel with error code P0602?

• Starting problems: The vehicle cannot be started or starts irregularly
• Engine performance: Significant loss of power and poor acceleration
• Idle behavior: Unsteady or fluctuating idling
• Fuel consumption: Increased consumption due to incorrect engine management
• Electronic systems: Failure of various vehicle functions
• Emergency running program: Engine only runs in emergency running mode with reduced power

How can the problem of error code P0602 be rectified?

• Fixing P0602 usually requires professional help, as it is a complex control unit problem.
• Reprogram the control unit: Professional reprogramming of the ECM/PCM with the correct software version by a specialist workshop with the appropriate equipment
• Battery test and replacement: Check the vehicle battery and charging system, as unstable voltage can lead to programming errors, replace battery if necessary
• Replace control unit: Replacing the defective engine control unit with a new or reconditioned unit with subsequent programming to the specific vehicle
• Check wiring: Check all power supply wiring to the ECM for damage, loose connections or corrosion and repair accordingly
• Perform software update: Install the latest available software version for the engine control unit via official manufacturer channels
• Complete system reset: Complete deletion of the ECU and reinstallation of the firmware with all vehicle-specific parameters