P06ED: Engine RPM Output Circuit Low

What it means

Same as P0654 with the output line shorted to ground. 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.

At a glance

• Usually lights the check-engine light

How it works

The engine RPM output circuit carries an engine-speed signal from the control system to another vehicle system or module. P06ED sets when the output circuit voltage is lower than expected, commonly because the line is shorted to ground or has a connection fault.

Common causes

Most likely first.

1. Output line shorted to ground
2. Connector pins corroded - high contact resistance
3. Harness chafing through insulation

Symptoms

• Check engine light on
• Possible limp mode or no-start
• Multiple follow-up faults across modules
• Reset/relearn may be needed after repair

How to diagnose it

1. Record freeze-frame data and scan other modules for missing or implausible engine-speed messages that could identify what is affected.
2. Use the wiring diagram to locate the engine RPM output circuit, then inspect its harness and connectors for chafing, water ingress, corrosion, or pushed-back pins.
3. With the fault active, monitor the output signal and gently move accessible sections of the harness to see whether the fault changes.
4. Disconnect components on the circuit as directed by the manufacturer's procedure, then check for a short to ground and compare circuit readings with the manufacturer's specification.
5. If the wire is not shorted to ground, check connector contact and continuity end to end for an open or high-resistance connection.
6. If the circuit and connections pass, follow the manufacturer's procedure to check the output source and receiving module.

Common fixes

• Repair chafed engine RPM output wiring that is contacting ground.
• Clean or repair corroded, loose, or pushed-back connector terminals.
• Repair a broken or high-resistance section of the output circuit.
• Repair a confirmed fault in the output source or receiving module after circuit tests pass.
• Clear the code and complete any required relearn after repair.

Can I keep driving?

Driving may be affected if another module loses the engine-speed signal, potentially causing warning lights, poor operation, or a no-start. If the engine runs abnormally or loses power, stop safely and have the fault checked before continuing.