P0473

P0473 is the opposite-rail fault from P0472 — the Exhaust Back Pressure sensor is reporting a voltage above the ECM's calibrated high threshold, typically above 4.5-4.8V on a 0-5V analog sensor. Cheapest-first ladder: (1) Pull the connector at the EBP sensor and inspect for green/white corrosion or a soaked pigtail — a corroded ground or shield pin pulls the signal wire up to reference voltage and looks identical to a stuck-high sensor. (2) Scan live data with the engine off: a healthy EBP sensor reads 0-0.3 psi at key-on engine-off (atmospheric). If it reports 30-50 psi at KOEO, the sensor is electrically pegged high — either internal sensor failure, a signal wire shorted to 5V reference, or a corroded connector. Cross-check by unplugging the sensor; if the PID drops to zero or to a default fault value, the sensor itself is bad; if it stays pegged high, the harness is shorted upstream. (3) Backprobe at the sensor connector with a DMM — signal pin should sit near 0.5V at KOEO with engine off; a reading near 5V confirms short-to-reference inside the sensor body or wiring. Verify expected ranges: 0-10 psi at idle for naturally aspirated gas, 5-30 psi for turbo gas under boost, 30-50 psi for diesel at full load with exhaust brake engaged. Expensive-misdiagnosis caveat: on Ford 6.0L/6.4L Powerstrokes, a P0473 is almost never the sensor itself — it's the EBP tube/pigtail harness chafing through against the exhaust manifold and shorting to the 5V reference; spend the 30 minutes inspecting the harness routing before ordering parts, because a $300 sensor doesn't fix a $0 chafing point.

Vehicle-specific patterns: 2003-2007 Ford 6.0L Powerstroke throws P0473 from harness chafe at the EBP sensor pigtail where it routes past the up-pipe — Ford addressed this in OEM service bulletins with a re-routing kit, but most shops just resleeve with high-temp loom and zip-tie clear of the manifold. 2008-2010 Ford 6.4L Powerstroke fails similarly but the sensor sits in a different location and the failure mode shifts toward sensor-internal short from heat soak. 2007-2016 Duramax LMM/LML reads EBP via a differential-pressure sensor across the DPF and a P0473 there usually means a kinked or split pressure-tube hose dumping reference air; inspect both lines before sensor replacement. 2007-2018 RAM Cummins 6.7L uses EBP as a primary input for the integral exhaust brake actuator, so a P0473 there typically kills brake-saver function and triggers a derate. 2009-2014 VW 2.0 TDI (Jetta, Passat, Golf) reads DPF differential pressure across the substrate and a stuck-high reading shows up as P0473 paired with regen-related codes; the differential-pressure hoses crack at the elbows. Common diesel concern: soot accumulation across DPF substrate inflates back pressure readings — run an active regen before condemning the sensor. Estimated repair: $40 (harness repair) to $550 (sensor + harness pigtail + labor).