P04A9 — Exhaust gas pressure control valve position sensor/switch B - circuit high

Generic OBD2

Generic OBD2: P04A9

Exhaust gas pressure control valve position sensor/switch B - circuit high

Reference namespace: obd2
Source revision: legacy-2.2.20

Generic OBD2 definition; confirm the protocol and vehicle-specific service information.

What should I check before using this definition?

Keep the full code, module, status and freeze-frame data. Confirm the vehicle’s make, model, year and current manufacturer service information before choosing a repair. This entry does not identify a failed part by itself.

Organize a scan report or recording

Source and applicability

OBD Lens production library legacy-owner-2026-11-02-v84-evidence. This is a scoped technical reference, not a scan of your car. A catalog relationship does not certify that every ECU, year or engine returns the same signal or code definition.

Read the reference method

What does P04A9 mean?

Exhaust gas pressure control valve position sensor/switch B - circuit high. 1 reference families define this identifier: Generic OBD2.

Is P04A9 a generic or manufacturer-specific code?

This code has a generic OBD-II prefix. Confirm the reference scope shown above.

Can P04A9 tell me which part has failed?

This entry does not identify a failed part by itself. Confirm the vehicle’s make, model, year and current manufacturer service information before choosing a repair.