P0468: Purge Flow Sensor Circuit High Input
The P0468 code indicates that the Engine Control Module (ECM) has detected a voltage signal from the purge flow sensor that is higher than the expected range. This sensor monitors the flow of fuel vapor from the charcoal canister to the engine intake during the evaporative emission (EVAP) system purge cycle. A high input typically means the sensor is reading excessive flow or there is a short to voltage in the circuit. This can lead to improper fuel mixture and increased emissions.
01. Most Common Causes
- Faulty purge flow sensor
- Short to voltage in the purge flow sensor circuit
- Damaged wiring or connector
- Corroded terminals
- ECM issue (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Rough idle or hesitation
- Poor fuel economy
- Failed emissions test
03. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for additional EVAP codes.
Step 2: Visually inspect the purge flow sensor and its wiring for damage, corrosion, or loose connections.
Step 3: Test the sensor's voltage signal with a multimeter; compare to manufacturer specifications.
Step 4: Check for a short to voltage by disconnecting the sensor and measuring voltage at the harness connector.
Step 5: If wiring and sensor are okay, test the ECM output to the sensor.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
Yes, but it may cause rough idle and poor fuel economy. It's best to diagnose and repair soon to avoid emissions issues.
How much does it cost to fix?▼
Typically $50-$150 for parts and labor, depending on the cause. A sensor replacement is usually under $100.