What it means
The EVAP pressure sensor/switch C reports a circuit low condition. Tank pressure plausibility for leak detection on this branch is impaired.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
EVAP pressure sensor/switch C measures pressure in the evaporative-emissions system so the control module can assess tank pressure during leak checks. This code sets when the C circuit signal is lower than the module expects, which can prevent reliable pressure readings.
Common causes
Most likely first.
- Signal wire shorted to ground
- Internal sensor short
- Connector pins corroded - high contact resistance
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
- Record freeze-frame data and check live EVAP pressure readings for an implausibly low or fixed value to confirm when the fault occurs.
- Inspect sensor C's connector and nearby harness for corrosion, damaged insulation, loose pins, or a signal wire contacting ground.
- With the wiring diagram, check the sensor's reference, ground, and signal circuits for shorts to ground or poor connections.
- Measure the signal while monitoring the circuit and compare it with the manufacturer's specification under the conditions in the freeze frame.
- If the wiring and connections pass, test sensor C itself against the manufacturer's specification before considering a control-module fault.
Common fixes
- Clean and secure corroded or loose sensor C connector pins.
- Repair a signal wire shorted to ground or damaged harness section.
- Replace the EVAP pressure sensor/switch C if its output remains low with sound wiring.
- Repair a confirmed reference or ground circuit fault.
Can I keep driving?
The code alone usually does not affect normal engine operation, but it can prevent EVAP leak monitoring and cause an emissions inspection failure. If you smell fuel, avoid driving near ignition sources and have the vehicle 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.