What it means
The exhaust pressure sensor A signal is intermittent or erratic. Possible causes include a sensor, wiring, connector, or pressure-passage problem.
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 through its passage and sends a changing signal to the control module. This code sets when that signal becomes intermittent or erratic, so the module cannot rely on it consistently.
Common causes
Most likely first.
- Intermittent connector
- Connector with intermittent contact under vibration
- Harness routed against vibrating component
Symptoms
- Check-engine light on
- Intermittent loss of power or sluggish acceleration
- Exhaust smoke may vary
- Fuel economy may fluctuate
How to diagnose it
- Record freeze-frame data and graph sensor A live pressure data to see whether dropouts coincide with vibration, temperature, or engine load.
- Inspect sensor A's connector for a loose lock, corrosion, moisture, or terminals that may lose contact under vibration.
- Trace the sensor A harness for chafing, heat damage, or contact with a vibrating component.
- Check the pressure tube and passage for a loose connection, blockage, leak, or damage that could cause fluctuating readings.
- With live data displayed, gently move the accessible sensor A connector and harness to see whether the reading jumps or drops out.
- Test the sensor A circuit for intermittent opens or shorts and test the sensor itself if the harness and pressure path remain sound.
Common fixes
- Reseat and secure sensor A's connector.
- Clean corroded terminals or replace terminals that do not maintain contact.
- Repair and secure harness sections that rub, overheat, or vibrate.
- Repair a leaking, blocked, or damaged pressure tube or passage.
- Replace exhaust pressure sensor A if its output remains erratic with a sound circuit and pressure path.
Can I keep driving?
Drive gently only if the engine remains predictable, and avoid towing or hard acceleration if power or smoke fluctuates. Stop if power loss becomes severe; intermittent pressure data can disrupt exhaust control and emissions performance.
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.