What it means
The exhaust pressure sensor A signal is outside the expected range or does not respond as expected. The cause may be the sensor, its wiring, or the pressure passage.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Exhaust pressure sensor A measures pressure delivered through its passage, and the control module checks whether the reading behaves plausibly as engine and exhaust conditions change. This code sets when the signal is electrically plausible but falls outside the expected range or responds incorrectly.
Common causes
Most likely first.
- Sensor drift
- Sensor element aged beyond calibration window
- Sensor mounting loose - signal damping
Symptoms
- Check-engine light on
- Possible reduced engine power or sluggish acceleration
- Possible increased exhaust smoke
- Possible reduced fuel economy
How to diagnose it
- Record freeze-frame data and compare sensor A live pressure data with engine speed and load to identify when the reading stops following expected changes.
- Inspect sensor A's mounting, connector, and wiring for looseness, corrosion, heat damage, or a connection that could damp or distort the signal.
- Check the pressure tube and passage for soot blockage, leaks, kinks, or damage that could make the sensor respond slowly or inaccurately.
- Compare the sensor reading under the conditions described in vehicle service information, including any specified engine-off check.
- Test sensor A's supply, ground, and signal wiring against the diagram and manufacturer's specification.
- If the passage and circuit are sound, test sensor A for drift or slow response and replace it if it fails the manufacturer's checks.
Common fixes
- Secure sensor A and its mounting if loose.
- Clear a blocked pressure passage or repair a leaking or damaged tube.
- Clean and reconnect the sensor A connector; repair damaged terminals.
- Repair wiring that causes an unstable or damped signal.
- Replace exhaust pressure sensor A if its reading remains inaccurate or slow with a sound passage and circuit.
Can I keep driving?
You may be able to drive gently if the engine has normal power and no unusual smoke, but avoid hard acceleration or towing if it feels sluggish. A faulty pressure reading can impair exhaust control and emissions performance, so arrange diagnosis soon.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.