What does code P1604 mean?

Q: What does code P1604 mean?

Internal Control Module Driver Error. P1604 on a Volkswagen means the engine control module (ECM) has detected an internal driver circuit fault, typically within its own output stage that commands a relay, solenoid, or actuator. The ECM monitors the driver's electrical behavior and sets this code when the expected voltage or current feedback does not match what the software commands.

DTC codes / Volkswagen codes / P1604

P1604 · VolkswagenInternal Control Module Driver Error

P1604 on a Volkswagen means the engine control module (ECM) has detected an internal driver circuit fault, typically within its own output stage that commands a relay, solenoid, or actuator. The ECM monitors the driver's electrical behavior and sets this code when the expected voltage or current feedback does not match what the software commands.

SystemPowertrain

Code typeVolkswagen specific

SeverityMedium

Fix difficultyProfessional

AreaComputer and output circuits

Guidance is general and written for Volkswagen vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.