P0466 Code: Purge Flow Sensor Circuit Range/Performance

What the P0466 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 P0466 code is a range fault. It means the sensor measures, but measures wrongly: wear, dirt, a clogged port or an abnormal real condition.

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.

This kind of fault is usually not solved with a multimeter, because electrically everything looks fine. You have to compare what the part says against reality: with a gauge, a thermometer, a vacuum pump, or by commanding the component with the scan tool and watching whether the physical result matches the command.

P0466 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 P0466 code

1. Degraded or dirty sensor. It gives believable but wrong readings.
2. Clogged port or hose on pressure sensors.
3. Abnormal real condition: a leak, a blockage or a temperature outside the normal range.
4. High resistance in the connector from corrosion.

How to diagnose the P0466 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 P0466 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.

P0466 on Chrysler

It is typical of some older Chrysler models.

P0466 on Ford

It is typical of some older Ford models.

Frequently asked questions about P0466