P24AE

Code

Generic P — Powertrain

Particulate Matter Sensor Circuit

Brand: Generic

Type: P — Powertrain

Views: UK: 45 EN: 261 RU: 53

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Page language: EN

Causes

Damaged or corroded connector or wiring to the PM sensor
Open or shorted signal, power or ground circuit
Faulty particulate matter (soot) sensor (internal failure)
Contaminated or physically damaged sensor element
Blown fuse or relay supplying the sensor/heater
Poor ground or high resistance in circuit

Symptoms

Malfunction Indicator Lamp (MIL) or check engine light illuminated
Reduced DPF monitoring accuracy; possible regen issues or forced regen events
Possible reduced engine performance or limp mode (manufacturer dependent)
Stored diagnostic trouble codes related to DPF or emission control
Visible soot smell or heavy exhaust smoke in severe cases

What to check

Read and record all stored codes and freeze frame data; note related DPF/pressure codes
Visually inspect PM sensor, connector and wiring for damage, corrosion, contamination or soot ingress
Check that the sensor connector is fully seated and locking tab engaged
Verify fuses and relays for sensor power/heater circuits
Backprobe sensor connector and measure reference voltage, signal voltage and ground with ignition ON and during engine conditions per OEM specs
Check continuity and resistance from sensor connector to ECM pins (for opens/shorts)

Signal parameters

Reference/supply voltage: typically 5.0 V (±0.25 V) or vehicle-specific; some sensors use 12 V for heater circuits — consult OEM specifications
Signal output: variable 0.1–4.9 V depending on soot concentration (varies by sensor type and manufacturer)
Heater supply: ~12 V when active; heater resistance typically tens to a few hundred ohms (vehicle-specific)
Sensor grounding: near 0 V when measured at chassis/ECM ground with good connection
Typical sensor-to-ECM continuity: near 0 Ω for ground, low ohms for power feed; signal circuit continuity should be low and without high resistance (values vary by harness length)
Note: exact values vary by vehicle and sensor model — always confirm with OEM data

Diagnostic algorithm

Connect a scan tool, read all DTCs and live data for PM sensor and related DPF parameters. Record freeze-frame data.
Perform a visual inspection of the PM sensor, connector, and wiring harness for damage, contamination or poor connections. Repair any obvious issues.
Check fuses/relays feeding the sensor and heater circuit. Replace if faulty.
With ignition ON (or per OEM), backprobe the sensor connector: verify reference voltage, ground and signal presence. Compare to expected ranges. If reference or ground is missing, trace/repair the circuit to the ECM.
Measure heater circuit voltage and sensor heater resistance (with connector disconnected if required). If heater not powered or resistance out of spec, inspect wiring and supply. Replace sensor if heater is internally open/shorted.
Perform continuity/resistance checks between sensor connector pins and ECM pins to detect opens or high-resistance joints. Repair wiring harness as needed.
Wiggle the harness and connector while monitoring live data to reproduce intermittent faults. Repair or replace damaged sections.
If electrical checks pass, inspect for sensor contamination or damage. Clean only if recommended by OEM; many PM sensors are non-serviceable and require replacement if contaminated.
After repairs or sensor replacement, clear codes and perform a drive cycle or forced regeneration (if required) while monitoring sensor output and DPF parameters to confirm normal operation.
If circuit checks and replacement do not resolve the issue, consider ECM diagnostics or reflashing; consult manufacturer procedure for ECM testing.

Likely causes

Loose, corroded, or disconnected connector at PM sensor
Open/shorted wiring between sensor and ECM (chafing, pinched, rodent damage)
Internal failure of PM sensor (common after exposure to oils/ash)
Blown fuse or lost power/ground to sensor/heater

Fault status

⚠️ Status

Particulate Matter Sensor Circuit fault — ECM detects abnormal or missing signal/power/ground from the PM sensor. May cause DPF monitoring issues and illuminate MIL. Electrical inspection and sensor verification required.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours