What does code P1399 mean?

Q: What does code P1399 mean?

Engine RPM Signal Short To B+. P1399 on Volkswagen vehicles means the engine control module (ECM) has detected a short to battery voltage on the engine speed (RPM) signal circuit, which is the signal the ECM uses to know how fast the engine is turning. The ECM monitors the voltage on this line and flags the code when the signal wire is pulled up to battery positive instead of pulsing normally.

DTC codes / Volkswagen codes / P1399

P1399 · VolkswagenEngine RPM Signal Short To B+

P1399 on Volkswagen vehicles means the engine control module (ECM) has detected a short to battery voltage on the engine speed (RPM) signal circuit, which is the signal the ECM uses to know how fast the engine is turning. The ECM monitors the voltage on this line and flags the code when the signal wire is pulled up to battery positive instead of pulsing normally.

SystemPowertrain

Code typeVolkswagen specific

SeverityMedium

Fix difficultyProfessional

AreaIgnition system and misfire

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