What does code P1638 mean?

Q: What does code P1638 mean?

Data Bus Powertrain Missing Message From Clutch Control. P1638 on Volkswagen vehicles means the engine control module (ECM) is not receiving the expected controller area network (CAN) message from the clutch control module over the powertrain data bus. The ECM has detected a communication timeout or missing message from the clutch system, which is critical for coordinating engine torque during gear changes on models with an automated manual or dual-clutch transmission.

DTC codes / Volkswagen codes / P1638

P1638 · VolkswagenData Bus Powertrain Missing Message From Clutch Control

P1638 on Volkswagen vehicles means the engine control module (ECM) is not receiving the expected controller area network (CAN) message from the clutch control module over the powertrain data bus. The ECM has detected a communication timeout or missing message from the clutch system, which is critical for coordinating engine torque during gear changes on models with an automated manual or dual-clutch transmission.

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.