What are the common causes of P0654?

An open in the engine RPM output wire. Corrosion at the tach output connector. A wiring fault between the PCM and the tachometer. A failed tachometer. A faulty PCM output driver.

Check that the tachometer reads engine speed. Inspect the RPM output wire and connector. Monitor the RPM output signal on a scan tool. Test the output circuit for an open. Repair the output circuit if the signal is missing at the tach. Clear the code and retest.

P0654

Engine RPM Output Circuit/Open

System: Computer output circuits (P code)
Lamp: Check Engine Light
Category: Powertrain - Computer and Auxiliary Controls

What it means

P0654 means Engine RPM Output Circuit/Open.

Check these first

An open in the engine RPM output wire
Corrosion at the tach output connector
A wiring fault between the PCM and the tachometer
A failed tachometer
A faulty PCM output driver

What to do next

Check that the tachometer reads engine speed
Inspect the RPM output wire and connector
Monitor the RPM output signal on a scan tool
Test the output circuit for an open
Repair the output circuit if the signal is missing at the tach
Clear the code and retest

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Updated

Generic SAE J2012 definition. Last updated 2026-10-10.