OBD-II Code P0472 — What It Means & How to Fix It

What Does This Error Mean?

P0472 means the exhaust pressure sensor is sending a voltage signal that is lower than the minimum expected value. The computer is seeing a signal that is too weak — basically, the sensor looks like it has lost power or is shorted to ground. This is mostly found on diesel-powered trucks and SUVs. You may notice reduced engine power, excessive smoke, or a rough idle.

Affected Models

Ford Super Duty trucks with Power Stroke diesel
Dodge/Ram trucks with Cummins diesel
GM trucks with Duramax diesel
Diesel vans and commercial vehicles
Some European diesel passenger cars

Common Causes

Short to ground in the sensor signal wire, pulling the voltage below the minimum threshold
Exhaust pressure sensor itself has failed internally and outputs too low a voltage
Corroded or damaged connector pins causing a poor connection and low signal
Wiring harness damaged by heat or abrasion, shorting the signal wire to a ground
Faulty PCM/ECM misreading the sensor voltage (uncommon)

How to Fix It

Start with the connector. Unplug the exhaust pressure sensor and inspect the connector pins. Look for corrosion, bent pins, or green/white residue indicating moisture intrusion.

Cleaning the connector with electrical contact cleaner and reconnecting it firmly fixes a surprising number of low-signal codes.
With the ignition on (engine off), use a multimeter to measure voltage at the signal pin of the sensor connector. You should see a reference voltage — typically 5V from the PCM.

If you see 0V or near 0V on the reference wire, the PCM may not be supplying power to the sensor. Check the fuse for the sensor circuit first.
Check the signal wire for a short to ground. Disconnect the PCM connector and the sensor connector. Measure resistance between the signal wire and any chassis ground — it should read infinite (no connection). If you get a low reading, there is a short.

A wiring diagram for your specific vehicle is essential for this step. Shorts are often caused by a wire rubbing against an exhaust heat shield.
Inspect the wiring harness from the sensor back to the PCM. Look for any spots where the harness runs near hot exhaust pipes, rubbing on sharp metal edges, or being pinched.

Even a tiny wire nick can create an intermittent short that logs P0472.
If all wiring checks out, replace the exhaust pressure sensor. Clear the code and run the vehicle through a full drive cycle to verify the repair.

Replacement sensors are inexpensive — usually $20 to $60. Always use a quality OEM or reputable aftermarket part.

When to Call a Professional

P0472 often requires a multimeter and wiring diagram to diagnose properly. If you are not comfortable checking wiring voltages, a shop can trace the circuit quickly. Expect a diagnosis fee of $75 to $125, plus $50 to $100 for the sensor if needed. Total repair is typically under $250.

Frequently Asked Questions

What does 'low input' mean for a sensor code?

Sensors send a voltage signal to the PCM that varies with pressure. Low input means that voltage has dropped below the minimum the PCM expects to see. It could mean the sensor itself failed, or there is a wiring fault pulling the signal low. The fix is to find out which one is causing the low voltage.

Can P0472 damage my engine if I ignore it?

On diesel engines, the exhaust pressure sensor helps manage the turbocharger and emissions systems. Ignoring it long-term can lead to improper turbo operation and reduced DPF regeneration. It is best to address this code within a few weeks.

How is P0472 different from P0473?

P0472 is a low signal — voltage is below the minimum expected value. P0473 is a high signal — voltage is above the maximum expected value. P0472 typically points to a short to ground or a failed sensor. P0473 typically points to a short to voltage or a different type of sensor failure.