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DTC codes / Nissan codes / P1677

P1677 · NissanTraction Control System FI Data Line Failure

P1677 on Nissan vehicles indicates a failure in the serial data communication line between the traction control system (TCS) module and the engine control module (ECM). The ECM has detected that the expected fuel injection (FI) data signal from the TCS is missing or corrupted, which can disable traction control and illuminate the warning light.

SystemPowertrain
Code typeNissan specific
SeverityMedium
Fix difficultyProfessional
AreaComputer and output circuits

Symptoms you may notice

  • Traction control system (TCS) warning light illuminated on the dashboard
  • Vehicle stability assist (VSA) or slip indicator light may also be on
  • Traction control system may be completely inoperative
  • Engine may enter limp mode or exhibit reduced power
  • Often no symptoms besides the warning light
  • Anti-lock braking system (ABS) light may illuminate if the fault affects shared data lines

Common causes, most likely first

  1. Damaged or corroded wiring in the data line between the TCS module and ECM
  2. Faulty TCS control module (internal communication failure)
  3. Poor electrical connection at the TCS or ECM connectors
  4. Faulty ECM (rare but possible)
  5. Water intrusion or corrosion in the harness or connectors
  6. Aftermarket accessories improperly tapped into the data circuit

How to diagnose and fix it

  1. Inspect the TCS and ECM connectors for corrosion, loose pins, or water intrusion
  2. Check the data line wiring for continuity, shorts to ground, or shorts to power using a multimeter
  3. Verify battery voltage and ground connections to the TCS module and ECM
  4. Perform a wiggle test on the harness while monitoring live data to detect intermittent faults
  5. Repair or replace any damaged sections of the data line harness
  6. If wiring is intact, substitute a known-good TCS module and retest
  7. If the fault persists, diagnose the ECM and replace if necessary

Don't replace the TCS module yet

  • A common misdiagnosis is replacing the TCS module when the real problem is a chafed wire in the harness near the firewall or under the battery tray.
  • The FI data line is a serial communication bus, so a fault in any module sharing that bus can set P1677 even if the TCS module itself is fine.
  • Aftermarket alarms or remote starters tapped into the data circuit often cause this code by introducing noise or voltage spikes.
  • The code can be stored intermittently due to a loose ground connection at the TCS module, which may not fail a simple continuity test.
  • Always check for related codes in the ABS and ECM systems; a single failed module can set multiple communication codes across different systems.

Can I keep driving with P1677?

You can usually drive the vehicle, but traction control and stability assist will be disabled, which reduces safety in slippery conditions. Avoid aggressive driving or towing, and have the fault diagnosed promptly to prevent further electrical issues.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

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

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