P0609: Control Module Vehicle Speed Sensor Output B
What to do
Driveable. Mention any aftermarket electrical installation.
What this code means
A fault in the second road speed output circuit — the counterpart of P0608, used where a vehicle feeds speed to more than one destination on separate circuits. Diagnosed identically, and aftermarket wiring is worth the same suspicion.
Likely causes
Start here
- Signal wire shorted to ground · moderate
- Aftermarket device wired into the circuit · moderate
- Broken wire in control circuit · moderate
Less common
- Failed control module · specialist
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
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