P0468 Code: Purge Flow Sensor Circuit High Input

What the P0468 code means

Some vehicles have a sensor that confirms the vapors from the canister are really flowing into the engine when the purge valve opens.

The sensor gets a 5 V reference and a ground from the computer and sends back a signal between roughly 0.5 and 4.5 V. The P0468 code is a high signal, which is usually caused by an open circuit (a loose connector or a cut wire) or by an interrupted sensor ground.

If the signal fails, the computer cannot verify the purge and turns on the check engine light. It does not usually affect driving, but it keeps the EVAP monitor from completing.

To confirm it, measure the continuity of each wire between the component connector and the computer connector with the key off. It should be less than 1 ohm, and an infinite reading means the wire is open. If the wiring is good, measure the component itself: infinite resistance confirms it is open inside.

P0468 code symptoms

• Check engine light on.
• EVAP monitor incomplete.
• Emissions monitor incomplete, so the vehicle cannot pass inspection.
• Often there are no other driving symptoms.

Likely causes of the P0468 code

1. Connector loose or broken. The most frequent cause.
2. Signal or ground wire cut, so the signal climbs up to the reference.
3. Sensor open inside, with infinite resistance.
4. Short to 5 V or 12 V from rubbing against another wire.

How to diagnose the P0468 code step by step

1. Read the sensor value on the scan tool and compare it with what you expect.
2. Inspect the connector for corrosion, water or loose pins.
3. Check the reference and ground with the key on (5 V, and less than 0.1 V of voltage drop on the ground).
4. Measure the signal with the connector plugged in and see whether it changes with conditions.
5. Do a wiggle test on the wiring.
6. Check continuity to the computer.
7. Command the purge with the scan tool and watch whether the signal changes.

How to fix the P0468 code

• Repair the connector or the wiring.
• Replace the sensor if the tests confirm it is bad.
• Correct the real condition if there is one (a leak or a blockage).
• Clear the codes and complete a drive cycle so the monitor runs.

Technical reference data

• 5 V reference, ground and signal.
• Approximate values only: check the manufacturer data for your engine.

Brand-specific notes

This is an uncommon code, found mostly on some older vehicles.

P0468 on Chrysler

It is typical of some older Chrysler models.

P0468 on Ford

It is typical of some older Ford models.

Frequently asked questions about P0468