P0452

P0452 is the fuel-tank pressure sensor reporting voltage below the expected operating range — typically below about 0.5V on a 5V-reference sensor. The ECU is reading a value that's electrically too low to be plausible, which usually means the sensor itself has failed shorted, the signal wire is shorted to ground, or the sensor's 5V reference has been lost. This is an electrical fault, so the smoke test isn't the first move; multimeter is. Backprobe the FTPS connector with key-on, engine-off: you should see a 5V reference on one pin, a ground on another, and a signal voltage typically between 1.5V and 3.5V depending on tank fill level. If the reference is missing, check the wiring back to the ECU and the ECU's other 5V-reference sensors (one open reference can take out multiple sensors on a shared circuit). If reference and ground are good and signal is stuck low, the sensor is shorted internally and needs replacement. The fuel cap is not the cause of P0452.

By platform: 2012+ Hyundai/Kia is again the highest-volume P0452 vehicle because of the underlying FTPS failure rate — sensor goes internally shorted, signal pulls low, code sets. 2005-2015 Toyota/Lexus P0452 is uncommon and is almost always a connector or wiring issue rather than the sensor itself. 2003-2010 Ford 4.6L sees occasional P0452 from corroded connectors at the tank; clean the connector and re-test before replacing the sensor. 2007-2014 GM trucks rarely throw P0452 — when they do it's almost always wiring damage from underbody impact or rodent activity. 2008-2015 VW/Audi don't typically throw P0452 because their EVAP architecture uses the LDP. Repair range: $0-20 for connector repair, $80-150 for sensor replacement, $200-400 if harness damage requires repair plus tank drop.