OBD-II Code P0473 — What It Means & How to Fix It

What Does This Error Mean?

P0473 means the exhaust pressure sensor is sending a voltage signal that is higher than the maximum expected value. The computer is seeing a signal that is too strong — essentially the sensor looks shorted to a power source. This code is common on diesel trucks and can cause limp mode or reduced power. It usually points to a wiring fault or a failed sensor.

Affected Models

Ford Super Duty with 6.0L, 6.4L, 6.7L Power Stroke
RAM 2500/3500 with Cummins diesel
Chevy Silverado/GMC Sierra with Duramax
Diesel-powered vans and motorhomes
European diesel cars with backpressure sensors

Common Causes

Short to voltage in the sensor signal wire, pushing the voltage above the maximum threshold
Exhaust pressure sensor has failed and is outputting a high, stuck voltage
Damaged wiring harness where a signal wire contacts a power wire
Corroded connector creating a false high reading
Extremely high actual exhaust backpressure due to a clogged DPF triggering the high limit

How to Fix It

First, check for other related codes on the scan tool. A clogged DPF will show P2002 or P2452. If those appear alongside P0473, high actual exhaust backpressure — not a sensor fault — is the likely cause.

Addressing the DPF issue is the priority in that case. P0473 may clear on its own once the DPF is cleaned or regenerated.
Inspect the exhaust pressure sensor connector and wiring. Look for any place where the signal wire could contact the vehicle's 12V supply or a switched power wire.

Heat damage from nearby exhaust components is a common cause of this type of short.
With the sensor disconnected and ignition on, use a multimeter to measure voltage on the signal pin of the harness side. It should show the reference voltage from the PCM (about 5V). If it reads higher, there is a short to a power source.

Backprobe the connector carefully to avoid damaging the terminal.
Disconnect the PCM connector as well and measure again. If voltage disappears, the short is in the wiring between the PCM and sensor. Trace and repair that section.

If voltage is still present with both connectors disconnected, an external power source is feeding the wire — this requires a full wiring trace.
If no wiring fault is found, replace the exhaust pressure sensor. Clear the code and run through a complete drive cycle to confirm the repair.

A failed sensor stuck at high output is less common than a wiring fault, but it does happen on high-mileage vehicles.

When to Call a Professional

Diagnosing a short to voltage requires a multimeter and a wiring diagram. A diesel specialist can trace this quickly with the right tools. If the DPF is clogged and causing genuinely high backpressure, a forced regeneration or DPF replacement may be needed. Expect $150 to $500 depending on the root cause.

Frequently Asked Questions

Can a clogged DPF really cause P0473?

Yes. If the diesel particulate filter is severely clogged, exhaust backpressure becomes extremely high. This can push the sensor's output voltage beyond the PCM's expected maximum range. Look for DPF-related codes alongside P0473 to confirm this is the cause. Forced DPF regeneration or replacement will resolve it.

Is P0473 serious enough to stop driving?

Not immediately in most cases, but reduced engine power or limp mode is common. The turbocharger may not operate correctly without accurate backpressure data. Have it diagnosed within a week to prevent potential damage to the turbo or emissions system.

How do I tell if the problem is the sensor or the wiring?

Swap the sensor with a known-good one and see if the code changes. Alternatively, use a multimeter to check the signal voltage with the sensor both connected and disconnected. If the high voltage disappears when you unplug the sensor, the sensor itself is the fault. If high voltage is still there with the sensor unplugged, the wiring is shorted.