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2017 TOYOTA HIGHLANDER
2.7L I4•FWD•AUTOMATIC•gas•1AR-FE
4 active safety recalls on this vehicle — view recalls
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Repairs0Labor477Torque4154Fluid10DTC1940Battery1Maintenance0Recalls4
P0863moderate severityPowertrain

TCM Communication Circuit

on 2017 Toyota Highlander 2.7L I4 · FWD

What this code means

The powertrain control module has lost communication with the transmission control module over the data circuit. This can prevent proper shift control and data sharing between modules.

Symptoms

  • Transmission warning light on
  • Erratic or harsh shifting
  • Limp mode activation

Common causes

  • Damaged wiring or connector at TCM
  • Faulty TCM
  • Corroded or loose ground connection
  • Faulty PCM

Diagnostic steps

  1. Scan for related communication codes
  2. Inspect TCM wiring and connectors
  3. Check ground and power at TCM
  4. Test data circuit continuity and voltage
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Other Powertrain codes on this vehicle

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