DPF Substrate Cracked or Damaged

What this code means

The DPF monitoring system has detected a signature consistent with a cracked or physically damaged DPF substrate, allowing soot bypass.

Symptoms

• Check Engine Light
• Visible soot in exhaust
• DPF differential pressure abnormally low
• Failed emissions opacity test
• Black exhaust under load
• Soot accumulation downstream of DPF

Common causes

• Thermal shock from water splash on hot DPF
• Mechanical impact or road debris
• Excessive regeneration temperatures
• Manufacturing defect
• Repeated ash cleaning cycles weakening substrate

Diagnostic steps

1. Measure DPF differential pressure at various loads
2. Compare upstream vs downstream soot levels
3. Inspect DPF for visible cracks or damage
4. Perform smoke opacity test downstream of DPF
5. Check for rattling noise from DPF area

Repair notes

Replace DPF. Cracked substrates cannot be repaired. Investigate cause of damage to prevent recurrence on new DPF.

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