What does code P1678 mean?

Q: What does code P1678 mean?

FPTDR Signal Line Failure. P1678 on Honda vehicles indicates that the powertrain control module has detected a failure on the FPTDR signal line, which is a dedicated communication circuit used for fuel pump control and diagnostics. The computer monitors the expected voltage or signal pattern on this line and sets the code when the signal is missing, out of range, or implausible for a calibrated period.

DTC codes / Honda codes / P1678

P1678 · HondaFPTDR Signal Line Failure

P1678 on Honda vehicles indicates that the powertrain control module has detected a failure on the FPTDR signal line, which is a dedicated communication circuit used for fuel pump control and diagnostics. The computer monitors the expected voltage or signal pattern on this line and sets the code when the signal is missing, out of range, or implausible for a calibrated period.

SystemPowertrain

Code typeHonda specific

SeverityMedium

Fix difficultyProfessional

AreaComputer and output circuits

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