P2403 indicates that the Powertrain Control Module has detected an open circuit in the sense line of the EVAP system leak detection pump. This means the pump’s sensor signal is not being received, preventing the system from verifying the pump’s operation.
A broken, corroded, or disconnected wire in the sense circuit prevents the signal from reaching the PCM.
The sensor that monitors pump operation can fail internally, resulting in an open circuit condition.
Loose pins, corrosion, or a bent connector can interrupt the sense signal.
A fuse that protects the pump sense circuit may have failed, cutting power to the sensor.
Rarely, the PCM’s input driver for the sense circuit can fail, but this is far less common than wiring or sensor issues.
No. In the overwhelming majority of cases the problem is wiring, connector, fuse, or the pump sense sensor itself. PCM replacement is only considered after all other possibilities have been eliminated.
The car will generally run, but the evaporative emissions system may fail inspection and fuel economy could be slightly reduced.
A loose or faulty fuel cap typically triggers EVAP leak codes (P0455‑P0459), not the pump sense circuit open code.
No. The pump motor circuit provides power to run the pump, while the sense circuit monitors the pump’s operation. Both have separate wires and fuses.