P2402

P2402 means the ECM is seeing the EVAP Leak Detection Pump control circuit stuck high — voltage on the control pin is sitting at battery voltage when the driver should be pulling it down to ground for activation, indicating an open low-side driver, an open control wire between the ECM and the pump, or an internally-open solenoid that won't sink current. With the pump connector unplugged you should read battery voltage on the supply pin and the control pin should float (high-impedance) until the ECM commands the pump on; during a commanded scan-tool activation the control pin should drop to under 1.0V while the ECM sinks the 0.3-0.8A of solenoid drive current. Cheapest-first ladder: unplug the connector and ohm-check the solenoid coil (30-80 ohms = healthy, infinite = open winding), back-probe the control pin during activation and look for the expected voltage drop, then continuity-check the control wire from the ECM connector to the pump connector (more than 5 ohms end-to-end = harness fault). 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 oxidized control-pin contact reads as a high-circuit fault even though the pump itself is fine.

Vehicle-specific patterns: 1998-2009 VW/Audi (Jetta, Passat, Golf, A4, A6) throws P2402 from oxidized pin contacts inside the rear-axle LDP connector — the connector terminals look mated but the contact resistance climbs past 50 ohms and the ECM sees the circuit as open. 1998-2008 Chrysler/Jeep/Dodge (Sebring, Wrangler, Grand Cherokee) NVLD/LDP combination units commonly throw P2402 from an internally-open solenoid coil that breaks at the lead-out weld inside the housing. 1996-2005 Mercedes-Benz (W202, W203, W211) throws P2402 from a failed EVAP relay in the rear SAM module that no longer supplies battery voltage to the pump on key-off. Common LDP repair pattern: replace pump + harness pigtail together; standalone pump replacement leaves the same root cause. Estimated repair: $180 to $700.