P24C6
PowertrainManufacturer-Specific - DPF Differential Pressure Sensor Performance
The DPF temperature sensor 'B' circuit has a fault. This is the second of two temperature sensors on the diesel particulate filter system, used to monitor regeneration temperatures and confirm the filter is working safely. With this signal missing or wrong, the ECU can't run regenerations properly.
ⓘ Information only. This page provides general educational information about fault code P24C6. We do not assess the urgency or safety implications of any specific fault. That requires in-person diagnosis by a qualified mechanic. Full terms.
Recommended next steps
Whether a fault is urgent, drivable, or routine depends entirely on the cause on a specific vehicle, and that can only be determined by a qualified mechanic with diagnostic equipment. If a warning light is illuminated, the most reliable next step is professional diagnosis.
What does P24C6 mean?
P24C6 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Manufacturer-Specific - DPF Differential Pressure Sensor Performance.
Symptoms commonly associated with this code
Symptoms that drivers often report alongside this code. Not all may apply to every case:
- • DPF warning light
- • Engine warning light
- • Possibly limp mode if the ECU shuts down regen attempts
- • Forced regenerations failing repeatedly, the DPF gets progressively more blocked
- • Sometimes a hot or burning smell during attempted regen, if the temperature monitoring isn't working safely
Possible causes
Causes commonly associated with P24C6, listed in approximate order of typical investigation. The actual cause on a specific vehicle can only be confirmed by professional diagnosis.
- 1. Failed temperature sensor (most common, the sensors live in the exhaust where temperatures are extreme)
- 2. Wiring damage from heat exposure, the loom near the DPF sees over 600°C during regen
- 3. Connector corroded or oily, exhaust environment is harsh
- 4. Sensor port carboned up, with the sensor reading false-low because it can't see exhaust gas through the buildup
- 5. Less commonly: ECU output stage fault on the input side
How mechanics typically diagnose
A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training.
- 1. Visual inspect the sensor and immediate wiring, look for heat-damaged insulation, oil contamination, or corrosion
- 2. Resistance-test the sensor against the manufacturer's spec at room temperature, typical reading is around 200-1,000 ohms cold
- 3. Read live data on both DPF temperature sensors, the values should track similarly during normal driving and diverge predictably during regen
- 4. Check the connector for damage or backed-out pins
- 5. If sensor and wiring are clean, condition has likely killed the sensor element internally; replacement is the answer
Common questions about P24C6
Why are there two DPF temperature sensors? +
The ECU monitors temperature both before and after the DPF (or before and during, depending on system) to manage regeneration safely. During regen, exhaust temperatures climb to 600-700°C briefly, and the ECU needs to confirm both that regen is reaching the right temperature and that it's not running too hot. Two sensors give the redundancy needed for safety. P24C6 is specifically about the second of the two.
Will a regen complete with this code? +
Usually no, the ECU won't run regeneration without confidence in the temperature monitoring. So the DPF gradually clogs because regens keep being aborted. Fix the sensor before the DPF blockage becomes severe enough to require a forced regen or replacement.
Can I run a regen manually with the code active? +
Most workshops won't because of the safety risk. The temperature monitoring exists to prevent runaway temperatures damaging the DPF or surrounding components. Once the sensor is fixed and codes cleared, a forced regen via scan tool or a long motorway run usually clears the soot accumulation that built up while the sensor was failed.
Manufacturer-specific notes
Some manufacturers publish additional definitions or variations for this code. Always cross-check with your vehicle's own service documentation.
Information only, not professional advice
The information on this page is provided for general guidance and educational purposes only. It is not a substitute for diagnosis or repair advice from a qualified mechanic. Always verify any fault before paying for repairs. carfaultcodes.co.uk accepts no liability for decisions made based on this information. Full terms →