What it means
The switching valve in the LDP - directs pump output between EVAP test path and reference orifice - has an open control circuit.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The leak detection pump switching valve routes pump flow between the EVAP test path and its reference path. P24BD sets when the control module detects an open in the valve's control circuit, so it cannot reliably command the valve.
Common causes
Most likely first.
- Open in valve or wiring
- Pin pushed back out of connector body
- Cracked solder joint inside the module or sensor
Symptoms
- Check engine light on
- Possible smell of fuel near tank or engine bay
- Failed emissions inspection
- Loose-cap warning may appear
How to diagnose it
- Save freeze-frame data and scan for related EVAP codes to determine whether the switching valve circuit fault occurred during a leak test.
- Locate the leak detection pump switching valve using vehicle service information and inspect its connector and harness for damage, corrosion, or a backed-out pin.
- Check the valve coil or actuator circuit for continuity and inspect the connector terminals for a poor connection, using the manufacturer's procedure.
- With the wiring diagram, test the control circuit between the module and valve for an open, including connector pin fit at both ends.
- If the circuit and connections pass, test the valve itself and the controlling module output according to the manufacturer's specification.
Common fixes
- Reseat or replace a pushed-back connector pin.
- Repair an open or damaged section of valve wiring.
- Replace the switching valve if its electrical winding or actuator is open.
- Repair a confirmed internal module connection fault if the valve and external wiring pass.
Can I keep driving?
The vehicle is generally driveable, but the EVAP system may not complete its leak test and emissions compliance can be affected. Get a strong or persistent fuel smell checked promptly.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.