P0654

Symptoms

• Check Engine light comes on
• The tachometer does not work or shows incorrect data
• Automatic transmission control system errors
• Cooling fan is not working properly
• Other electronic systems report RPM errors

Causes

• Broken wire in the RPM output circuit from the ECU
• Output short circuit
• Damage to the wiring harness in the ECU area
• Malfunction of the ECU output stage (RPM signal conditioner)
• Malfunction of the instrument panel or other RPM signal consumer

How to Fix

1. Check the tachometer operation with the engine running
2. Check the presence of the RPM output signal on the corresponding ECU pin with an oscilloscope
3. Inspect the RPM signal wire from the ECU to the dashboard and other consumers
4. Check the serviceability of the instrument panel unit (tachometer)
5. If there is no signal at the ECU output - diagnostics of the internal output stage of the ECU

Related codes

Error P0654 by Vehicle Brand