P24B3: Particulate Matter Sensor Heater Control Circuit Open

What it means

The PM sensor heater (regenerates the sensor by burning off accumulated soot) has an open control circuit.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

The PM sensor has a heater that raises its temperature so it can operate and burn off accumulated soot. The control module monitors the heater control circuit, and this code sets when the circuit is open and the heater cannot be controlled as expected.

Common causes

Most likely first.

1. Open in heater or wiring
2. Pin pushed back out of connector body
3. Cracked solder joint inside the module or sensor

Symptoms

• Check-engine light on
• Possible emissions warning
• Possible reduced engine power

How to diagnose it

1. Capture freeze-frame data and check for related PM sensor or aftertreatment codes that may help identify a shared power or wiring issue.
2. Inspect the PM sensor heater connector for a backed-out pin, corrosion, heat damage, or a loose fit.
3. Trace the heater wiring for breaks, chafing, or damage near the hot exhaust.
4. Check the heater circuit for continuity and verify its power and control paths against the manufacturer's wiring information.
5. If the external circuit is intact, test the sensor heater and control module circuit using the manufacturer's procedure.

Common fixes

• Reconnect a loose heater connector and secure its terminals.
• Repair an open or heat-damaged section of heater wiring.
• Replace a damaged connector or terminal that has pushed back.
• Replace the PM sensor or repair its internal heater connection if testing confirms an internal open.

Can I keep driving?

If the engine runs normally, limited driving to a repair location is generally reasonable, but do not ignore reduced power or an aftertreatment warning. The inactive heater can interfere with PM sensor readings and emissions control.