P24AE: Particulate Matter Sensor Circuit
What to do
The car will almost certainly drive normally, and this still needs attention. This sensor is the one that checks the particulate filter is doing its job, so with it faulty the car cannot prove its emissions system works — which is an MOT problem before it is a driving one.
Ask for the connector and wiring under the car to be inspected first. The sensor lives in the exhaust stream where road salt and water reach it, and corrosion there is a common cause and a cheap fix.
Mention any recent work under the vehicle — exhaust repairs, a filter change, or anything that involved unplugging things underneath — since a disturbed connector is a frequent cause.
What this code means
A general electrical fault has been detected in the particulate matter sensor circuit.
This sensor is easily confused with the pressure sensors on the same filter, and it does something completely different. A differential pressure sensor infers how full the filter is from how much it restricts the flow. A particulate matter sensor measures soot in the gas directly, after the filter, and its job is to catch a filter that has failed — cracked, melted, or removed — and is letting particulates straight through.
It works by collecting soot on an electrode pair and measuring the current that starts to flow once enough conductive carbon bridges the gap. Then it burns itself clean with an internal heater and starts again, so its normal operating cycle is accumulate, measure, regenerate, repeat.
That construction explains the failure modes. It carries a signal circuit, a heater circuit and a supply, and this code covers a general fault on the sensor circuit without narrowing which.
This is the family's front door and the least specific member of it. Where a low, high, intermittent or heater code is stored alongside, that one is the useful diagnosis.
Check the connector before the sensor. It sits under the vehicle in the exhaust stream, exposed to road salt and water, and corroded pins are a more common finding here than a failed element.
Likely causes
Start here
- Corroded or loose connector · easy
- Faulty particulate matter sensor · moderate
Less common
- Damaged wiring harness · moderate
- Water ingress into connector · easy
- Sensor left disconnected after previous work · easy
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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