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P0472 – Exhaust Pressure Sensor Low (OBD2)

P0472 means "Exhaust Pressure Sensor Low". The voltage the control unit measures in the exhaust back pressure sensor / control valve circuit is below the permitted minimum. For a sensor this usually means the signal wire is shorted to ground or the reference voltage is missing; for an actuator, that its control wire is shorted to ground.

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P0472 quick summary

Fault codeP0472
MeaningExhaust Pressure Sensor Low
SystemPowertrain (Engine & Transmission)
VehiclesGeneric OBD2
SeverityMedium
Can I drive?Usually yes, gently, but expect reduced power or limp mode. Have it checked soon.
Repair cost€30 – €600

How the exhaust pressure sensor and control valve work

Diesel engines use an exhaust pressure sensor and sometimes an exhaust pressure control valve (exhaust brake/flap) to monitor and control back pressure for EGR, DPF and warm-up.

The exhaust back pressure sensor measures pressure in the exhaust manifold or before the turbocharger. The control unit uses it for EGR control, turbo control and to detect blockages. An exhaust pressure control valve (exhaust flap) can be closed to raise back pressure – for faster warm-up, more EGR or an exhaust brake on commercial vehicles.

Codes P0470–P0474 cover the sensor and P0475–P0479 the control valve. The sensor port and its pipe are exposed to soot and condensation, so blockages and cracked pipes are common causes besides electrical faults.

A wrong back pressure reading can cause limp mode, incorrect EGR operation and turbo control problems; a stuck flap reduces power and raises exhaust temperatures.

On VAG vehicles (VW, Audi, Škoda, Seat, Cupra), VCDS and older VAG testers can show this code as the five-digit VAG code 16856 (P0472). Both numbers mean the same fault.

Symptoms of P0472

  • Check Engine light on
  • Reduced power or limp mode
  • Turbo or EGR related codes
  • Black smoke
  • Slow warm-up (stuck exhaust flap)

Most common causes of P0472 (most likely first)

Mechanic's Pro Tip

Most exhaust pressure sensor codes on diesels are not the sensor but the small steel or silicone pipe to it – blocked with soot or cracked. Clean it before buying a sensor.

  1. 1.Signal or control wire shorted to ground

    Most likely

    Look for chafed insulation where the harness touches the engine, exhaust brackets or body edges.

  2. 2.Missing 5 V reference or supply voltage

    An open reference wire or a shorted sensor elsewhere on the same reference circuit can pull it down.

  3. 3.Internal short in the exhaust back pressure sensor / control valve

  4. 4.Blocked sensor pipe or port (soot, condensation)

  5. 5.Cracked or disconnected sensor pipe

  6. 6.Failed exhaust pressure sensor

  7. 7.Sticking exhaust pressure control valve or actuator

Step-by-step diagnostic guide

  1. 1

    Read codes and pressure values

    Read all codes and check the exhaust pressure value with the engine off (should equal atmospheric pressure) and when revving.

  2. 2

    Measure the signal voltage

    With the ignition on and the exhaust back pressure sensor / control valve plugged in, back-probe the signal wire. Then unplug it and check the reference/supply and ground wires separately.

    Multimeter: Signal near 0 V = short to ground or no reference. Reference wire: about 5 V with ignition on. Signal wire to ground with connector unplugged: no continuity.

  3. 3

    Check the sensor pipe

    Remove and clean the pipe and port; check for cracks and correct routing.

  4. 4

    Check the sensor electrically

    Measure 5 V reference, ground and signal at the connector.

    Multimeter: Key on, engine off: reading close to barometric pressure.

  5. 5

    Test the control valve

    Command the valve with the scan tool and check that it moves freely; check its vacuum supply or electrical actuator.

  6. 6

    Replace and verify

    Replace the faulty part, clear codes and check readings on a test drive.

Frequently asked questions

Can I keep driving with P0472?

Usually yes, gently, but expect reduced power or limp mode. Have it checked soon.

How much does it cost to fix P0472?

Typical repair costs are 30 € – 600 €, depending on the cause and the vehicle. The most common fixes are: signal or control wire shorted to ground; missing 5 V reference or supply voltage; internal short in the exhaust back pressure sensor / control valve. Always confirm the cause with the tests above before buying parts.

What does the exhaust pressure sensor do?

It measures back pressure in the exhaust, which the control unit uses for EGR and turbo control and to detect blockages.

Is it the same as the DPF differential pressure sensor?

No. The DPF sensor measures the pressure difference across the particulate filter; the exhaust pressure sensor measures absolute pressure before the turbo or in the manifold.

What is the difference between P0472 and similar codes?

P0472 belongs to a group of codes for the same component that differ in the type or location of the fault: P0470 – Exhaust Pressure Sensor Malfunction; P0471 – Exhaust Pressure Sensor Range/Performance; P0473 – Exhaust Pressure Sensor High; P0474 – Exhaust Pressure Sensor Intermittent; P0475 – Exhaust Pressure Control Valve Malfunction; P0476 – Exhaust Pressure Control Valve Range/Performance. The tests on this page apply to the whole group; the type of fault tells you where to start.

Related fault codes

This guide is for information only. Working on vehicles can be dangerous — if you are unsure, have the car checked by a qualified mechanic. Values can differ between model years; always check the manufacturer's repair information.