P2CA4
Particulate Filter Pressure Sensor Signals Swapped A/B
The ECM detects that the particulate filter pressure sensor signals A and B are reversed - low-pressure side reads as high-pressure side and vice versa. Most likely a wiring swap during service.
The ECM detects that the particulate filter pressure sensor signals A and B are reversed - low-pressure side reads as high-pressure side and vice versa. Most likely a wiring swap during service.
Common causes
- high
Sensor connectors A and B swapped during service
One of the most commonly reported causes for this code — check this first.
Typical part cost: $10-110
- medium
Sensors installed in wrong positions
A plausible cause — test and verify before replacing parts.
Typical part cost: $10-110
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First things to check
- 1Confirm the code with a scan tool and check for additional related codes.
- 2Inspect the relevant sensors, wiring, and connectors for damage or corrosion.
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Related codes
See related trouble codes
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Frequently asked questions
What does P2CA4 mean?
P2CA4 means "Particulate Filter Pressure Sensor Signals Swapped A/B". It is a generic OBD-II code that points to a fault in the auxiliary emission controls.
What are the most common causes of P2CA4?
sensor connectors a and b swapped during service; sensors installed in wrong positions — these are the most commonly reported causes. Verify with a proper diagnosis before replacing parts, or use the Wrenchify app for a vehicle-specific diagnosis.
Can I keep driving with this code?
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical. Use the Wrenchify app for a full diagnosis specific to your vehicle.
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