Code result

P0739

TCM Engine Speed Output Circuit High

High severity

What it means

Same as P0737 with the output shorted to supply. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.

Is it safe to drive?

No — stop driving

This code points to a problem that can cause damage or affect safety. Avoid driving and have the vehicle diagnosed promptly.

Most likely causes

  • Output line shorted to supply

    high

    One of the most commonly reported causes for this code — check this first.

  • Connector pins corroded - high contact resistance

    low

    Less common, but worth ruling out after the more likely causes.

  • Supply wire pinched against B+ source

    low

    Less common, but worth ruling out after the more likely causes.

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