The evaporative monitor could not create or hold the expected vacuum or pressure, or it detected flow consistent with a large leak.
Why this matters
A trouble code reports a monitored result. It narrows the system and test conditions, but it rarely names the failed part by itself.
Evidence to capture first
- Fuel level and freeze-frame conditions
- Cap or capless seal condition and visible hose damage
- Vent closure, purge sealing, pressure-sensor response, and low-pressure smoke evidence
A disciplined path
- Inspect the service information and system diagram
- Verify capless or cap sealing without forcing parts
- Command or isolate the vent and purge paths as specified
- Apply approved low-pressure smoke and watch both leak location and sensor response
Decision point
The repair is supported when the failed circuit, mechanical condition, or monitored response is measured and the original monitor can run without the fault returning.
Source desk
Use current model-specific service information for specifications, connector locations, disabling procedures, and tightening values. The following public resources support the broader safety or system context used in this guide.
KEEP EXPLORING
Related guides
U0100 Lost Communication With ECM/PCM: Network Triage
Another module reported that expected communication with the engine or powertrain controller was absent.
Read guide
P0562 System Voltage Low: Battery, Charging, or Connection?
A control module measured supply voltage below its calibrated threshold for the required time.
Read guideP0135 Oxygen Sensor Heater Circuit: Test the Circuit
The controller detected an electrical or performance fault in the bank 1 sensor 1 heater circuit.
Read guide