Code result
P0864
TCM Communication Circuit Range/Performance
High severity
What it means
The Transmission Control Module communication circuit reports a communication circuit range/performance fault. Data exchange between TCM and ECM is impaired.
Is it safe to drive?
No — stop driving
This code can put the vehicle into limp or reduced-power mode. Avoid extended driving and have the vehicle diagnosed promptly.
Most likely causes
Communication bus fault
highOne of the most commonly reported causes for this code — check this first.
TCM internal fault
mediumA plausible cause — test and verify before replacing parts.
Gateway module routing CAN messages incorrectly
lowLess common, but worth ruling out after the more likely causes.
Related help
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