P0473 — Exhaust Pressure Sensor "A" Circuit High

powertrain (engine/transmission)

Is it safe to drive?

Repair P0473 promptly Driving is usually possible with P0473, but continued operation may reduce engine control accuracy on some vehicles. Arrange diagnosis promptly, and stop driving if a check-engine light is accompanied by severe misfire, overheating, smoke, or major loss of power.

Typical symptoms

The check-engine light may illuminate with P0473 stored in the control module
P0473 may appear as a confirmed or pending code during an OBD2 scan
The vehicle may otherwise drive normally because exhaust pressure sensor "A" is often used primarily for diagnostics and emissions control
On vehicles where sensor "A" influences engine or boost control, a high-input fault may cause hesitation, rough operation, or reduced power
Freeze-frame data may show P0473 occurring during acceleration, idle, or a specific operating temperature

Common causes

A short to battery or sensor-supply voltage in the exhaust pressure sensor "A" signal wiring
Corroded, loose, heat-damaged, or high-resistance connector terminals
An open circuit or poor ground/reference connection in the sensor harness
A failed exhaust pressure sensor "A" with an internally shorted or drifted circuit
A pinched or improperly routed wire after a previous exhaust-system repair
A blocked, cracked, or misaligned sensor tube that exposes the sensor to abnormal exhaust pressure
A less-common fault in the control module input or its corresponding harness terminal

How to diagnose with an OBD scanner

Inspect sensor "A" and its wiring With the ignition off, locate the exhaust pressure sensor designated as sensor "A". Inspect the connector, wiring near the hot exhaust, and sensor tube for burned pins, corrosion, chafing, cracks, or improper routing.
Read P0473 with an OBD2 scanner Connect an ELM327 adapter and use AIScanAuto or another OBD2 scanner to read stored, pending, and permanent codes. Save the P0473 freeze-frame information, and check the live sensor voltage if the vehicle supports that data parameter.
Test reference, ground, and signal voltage Using the manufacturer wiring diagram, back-probe the sensor "A" circuit at the sensor and control-module connector. Verify reference voltage, ground voltage drop, and signal voltage against model-specific specifications; a high signal with a shorted or damaged circuit can set P0473.
Separate the sensor fault from the harness fault After documenting the readings, disconnect sensor "A" and evaluate the circuit at the control-module connector. If the high reading disappears, test or replace the sensor; if it remains, repair the harness, connector, ground, or control-module input as applicable.
Repair and confirm the P0473 repair Repair damaged terminals or wires, clear the codes with the scanner, and operate the vehicle through a complete drive cycle. Confirm that P0473 does not return and that live sensor data remains within the manufacturer-specified range.

Approximate repair cost

A typical independent-shop estimate for diagnosing and repairing P0473 is roughly USD 250-900, depending on sensor accessibility and whether the fault is a loose connector, damaged wiring, or a failed sensor. Figures are estimates and vary by region.

Common questions

What does P0473 specifically mean?

P0473 means the control module detected an excessively high input from the exhaust pressure sensor "A" circuit, exceeding the manufacturer-defined electrical threshold.

Is P0473 more likely to be a sensor or a wiring problem?

Either can cause P0473. Corroded connectors, damaged wiring, and short-to-power conditions should be inspected before the exhaust pressure sensor "A" is replaced.

Can I safely drive my vehicle with P0473 stored?

Usually yes, because P0473 often has little immediate effect on drivability, but the fault should be diagnosed before the code clears or additional powertrain codes appear.

What should be checked first when P0473 is present?

Start with the sensor "A" connector and nearby wiring, then use live data and voltage measurements to determine whether the high input originates in the sensor or harness.

When your check engine light comes on and a scan tool reports P0473, the powertrain control module has detected a problem with the exhaust pressure sensor circuit. The sensor designated as "A" is sending a voltage signal that reads abnormally high — essentially at or near battery voltage instead of the expected operating range. This is classified as a "circuit high" condition, which the ECU flags because the data no longer falls within acceptable parameters.

The exhaust pressure sensor monitors backpressure in the exhaust stream. That information helps the engine computer manage emissions systems like exhaust gas recirculation, turbocharger wastegate operation, and diesel particulate filter regeneration. When the sensor circuit shows a sustained high voltage, the module loses reliable pressure data and can no longer make accurate adjustments. To prevent running the engine with corrupted inputs, the control unit requires the fault to appear repeatedly under specific driving conditions before illuminating the warning light. The freeze frame data stored alongside P0473 captures exactly what was happening — engine load, RPM, temperature, vehicle speed — when the malfunction was detected. Use that snapshot to recreate the conditions during testing.

Symptoms of P0473

The check engine light remains illuminated or flashes intermittently
Engine performance may be reduced, with the vehicle entering limp-home mode
The emissions-related system (EGR, turbo, or DPF) operates erratically or shuts down completely
Fuel consumption rises noticeably compared to normal driving
In some cases, the problem comes and goes with connector movement or temperature changes

Common Causes

A failed sensor pulling the signal line high is the most frequent culprit, but the issue can just as easily originate in the wiring or connectors.

Faulty exhaust pressure sensor "A" internally shorted and driving the signal voltage up
Broken or corroded connector at the sensor or harness junction
Signal wire shorted to a power source somewhere in the harness
Open ground circuit for the sensor, preventing proper voltage reference
Blown fuse feeding the sensor circuit
Chafed or melted wiring insulation causing intermittent shorts
Poor ground connection at the engine or body
Control module output driver failure (rare but possible)

How to Diagnose P0473

Approach the diagnosis systematically, starting with non-invasive checks before pulling components apart.

Connect an OBD2 scanner, confirm P0473 is active, and record the freeze frame data — note engine load, RPM, coolant temperature, and vehicle speed at the moment of failure.
Search for any manufacturer TSBs (technical service bulletins) tied to this code for your specific make and model; factory updates or known fixes may exist.
Visually inspect the exhaust pressure sensor connector and the surrounding harness for damage, moisture intrusion, corrosion, or loose pins.
With the sensor unplugged, measure signal voltage at the harness connector — if it reads high with the sensor disconnected, the harness has a short to power that must be traced.
If the voltage drops to normal with the sensor unplugged, test the sensor itself for proper resistance values and voltage output against specifications.
Perform a wiggle test on the harness while monitoring live data — any signal dropouts point to broken conductors inside the insulation.
After repairs, clear the code and complete a drive cycle matching the freeze frame conditions to verify the problem does not return.

Repair Options and Costs

Costs vary depending on which component actually failed. Independent shop rates typically break down as follows.

Wiring harness repair or connector replacement: $80–$250
Exhaust pressure sensor or associated actuator replacement: $150–$500
Control module repair or replacement: $300–$1,000

Always inspect connectors and wiring before committing to expensive component replacement. In the majority of cases, a simple wiring repair or connector fix resolves P0473 at the lower end of the cost spectrum. Labor rates vary by region, so call around for estimates based on your specific vehicle.

Driving Safety with P0473

For most vehicles, P0473 does not render the car undriveable. You can typically continue driving with the understanding that certain emissions functions may be disabled and performance could be slightly reduced. However, if the fault triggers limp mode, causes stalling, or produces warnings related to braking or steering, treat the situation as urgent and have the vehicle inspected as soon as possible.