P2407

P2407 means the ECM is seeing the LDP pressure-sense signal flicker or drop out intermittently — the value is mostly in range and mostly tracking the pump cycle, but the ECM is catching occasional out-of-band spikes or dropouts that fail the rationality monitor without holding long enough to set a hard P2403/P2405/P2406. This is the classic loose-connector / corroded-pin signature: the signal works most of the time but glitches when the harness gets bumped, when the underbody heats up, or when road vibration shakes the rear subframe. Cheapest-first ladder: data-log the sense voltage on a freeze-frame-capable scanner during a real drive cycle (wiggle test the harness while logging — any voltage spike during a wiggle is your answer), check for green corrosion under the connector boot at the rear-axle pump, and current-test the sense ground return for resistance variance under load (more than 0.2 ohms variance during a wiggle = intermittent ground). The diagnostic step that catches 80% of P2407s in 10 minutes: pop the connector boot, look for moisture or green corrosion, and reseat the pins. Expensive misdiagnosis caveat: VW/Audi/Chrysler LDP is mounted in a notorious water-collection point above the rear axle — corrosion at the connector is the #1 root cause; replace the pigtail before replacing the pump, because an intermittent code is almost always wiring and almost never the sensor itself.

Vehicle-specific patterns: 1998-2009 VW/Audi (Jetta, Passat, Golf, A4, A6) is the textbook P2407 vehicle — the rear-axle LDP connector is the single most common intermittent-fault location in the entire EVAP system on these platforms, and the fix is almost always a fresh pigtail. 1998-2008 Chrysler/Jeep/Dodge (Sebring, Wrangler, Grand Cherokee) NVLD/LDP combination units throw P2407 from heat-soak intermittents — the connector seal degrades and lets moisture cycle in/out with the underbody temperature. 1996-2005 Mercedes-Benz (W202, W203, W211) throws P2407 from a marginal sensor splice inside the canister assembly that flexes with vibration. Common LDP repair pattern: replace pump + harness pigtail together; standalone pump replacement leaves the same root cause. Estimated repair: $180 to $650.