P1605high severityPowertrain

A/T Diagnostic Communication Line

on 2016 Infiniti Q70L 3.7L V6 · RWD

What this code means

Failure in communication between ECM and TCM.

Symptoms

  • CEL
  • Trans stuck in failsafe
  • No shifting past 2nd/3rd
  • Overdrive light off

Common causes

  • Blown A/T fuse
  • Faulty TCM
  • Damaged communication wiring
  • Corroded connectors

Diagnostic steps

  1. Check A/T fuse
  2. Test communication line
  3. Inspect connectors
  4. Test TCM

Repair notes

Repair communication line or replace fuse.

Other Powertrain codes on this vehicle

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