P24C8

Code

Generic P — Powertrain

Particulate Matter Sensor Temperature Circuit Low

Brand: Generic

Type: P — Powertrain

Views: UK: 28 EN: 76 RU: 34

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Page language: EN

Causes

Open or short in the PM sensor temperature wiring (short to ground)
Corroded, loose or damaged connector at the PM sensor
Failed particulate matter sensor (internal temperature element shorted)
Blown fuse or loss of reference power or ground to the sensor circuit
Faulty PCM/ECM or poor PCM ground
Water/contamination or mechanical damage to the sensor

Symptoms

Malfunction indicator lamp (MIL) or diesel service light illuminated
DPF regeneration inhibited or limited; possible reduced engine power or limp-home behavior
Stored or pending DPF/soot-related codes
Possible trouble starting in cold conditions (if system relies on temp input)
No obvious engine noise changes—problem is typically electrical rather than mechanical

What to check

Read freeze frame and freeze data; capture live PID for PM sensor temperature and related signals
Confirm other DPF/PM codes present (pressure sensor, regeneration faults)
Perform visual inspection of sensor, connector and wiring for damage, corrosion, contamination or loose pins
Backprobe sensor connector and measure reference voltage, sensor signal and ground with a multimeter or scope
Check for continuity to PCM and for short to ground on the signal circuit
Verify fuses and PCM grounds relevant to the PM sensor circuit

Signal parameters

Typical sensor signal voltage expected range: ~0.5–4.5 V (varies by manufacturer); fault flagged when signal is below expected low threshold (often
Reference supply (if present) commonly 5 V or switched ignition supply—verify nominal value at connector
Temp sensor resistance (NTC style) will change with temperature; measure resistance at ambient and compare to spec
Heater circuit (if integrated) should show correct supply voltage (~12 V when commanded) and expected current draw per spec

Diagnostic algorithm

Retrieve all stored codes and freeze frame data. Note conditions when fault set (engine temp, ignition status).
Visually inspect sensor, connector and harness from sensor to PCM for damage, corrosion or fluid intrusion. Repair any obvious issues.
With ignition ON (engine OFF), backprobe connector: confirm reference supply voltage and ground continuity to PCM. Record values.
Measure sensor output voltage with ignition ON and at operating temperature (if safe). Compare to expected range. A reading
Check continuity of signal wire to PCM and check for short-to-ground. Repair wiring faults as needed.
Measure sensor resistance (if service manual gives values) at ambient. Replace sensor if resistance is out of expected range or shows short.
Inspect and test any sensor heater circuit: verify supply, ground switching and current draw when commanded by the PCM.
If wiring and connector are good and sensor tests out-of-spec, replace the particulate matter sensor and clear codes. Retest under drive conditions.
If fault persists after sensor replacement, suspect PCM/module fault — perform manufacturer diagnostics for module output/input testing before replacing.

Likely causes

Damaged wiring harness (abrasion, pinched, rodent damage) causing low voltage or short to ground
Corroded connector terminals at the PM sensor
Internal failure of the PM sensor temperature element (shorted thermistor)
Lost sensor ground or reference from PCM
Intermittent connection causing low/erratic readings

Fault status

⚠️ Status

PCM detected abnormally low signal from particulate matter sensor temperature circuit (low voltage/low resistance). DTC P24C8 set. Possible wiring short to ground, sensor failure, or lost reference/ground; DPF regeneration or related controls may be affected.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours