What causes P1678 on a Honda?

Poor connections or loose wires at the ABS/TCS control unit or PCM Failed ABS/TCS control unit dropping the FPTDR signal Failed PCM no longer receiving the traction signal Wiring break or short in the FPTDR signal line Corroded 16P connector at the ABS/TCS control unit

How do I fix P1678 on a Honda?

Reset the PCM, start the engine and wait 60 seconds to see if the code returns Check for poor connections or loose wires at the ABS/TCS control unit and PCM Disconnect the ABS/TCS 16P connector and retest to isolate the side at fault Substitute a known-good ABS/TCS control unit or PCM to confirm before replacing Verify the repair with a road test including a traction event

P1678 FPTDR Signal Line Failure

Q: What does P1678 mean on a Honda?

P1678. FPTDR Signal Line Failure. Applies to Odyssey, Accord, Pilot with traction control.

Category: Network Communications
Severity: Check Engine Light
Applies to: Odyssey, Accord, Pilot with traction control

This fault is part of the Honda ABS and VSA warning light guide. It covers the system and the order to check it.

What does P1678 mean on a Honda?

P1678. FPTDR Signal Line Failure. This Honda-enhanced code applies to Odyssey, Accord, Pilot with traction control.

Common causes of P1678

Poor connections or loose wires at the ABS/TCS control unit or PCM
Failed ABS/TCS control unit dropping the FPTDR signal
Failed PCM no longer receiving the traction signal
Wiring break or short in the FPTDR signal line
Corroded 16P connector at the ABS/TCS control unit

How to fix P1678

Reset the PCM, start the engine and wait 60 seconds to see if the code returns
Check for poor connections or loose wires at the ABS/TCS control unit and PCM
Disconnect the ABS/TCS 16P connector and retest to isolate the side at fault
Substitute a known-good ABS/TCS control unit or PCM to confirm before replacing
Verify the repair with a road test including a traction event

Sources and review

Last updated 2026-09-07.