P243C

Code

Generic P — Powertrain

Particulate Filter Regeneration Frequency Bank 2

Brand: Generic

Type: P — Powertrain

Views: UK: 31 EN: 70 RU: 41

AI status

Completed

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Page language: EN

Causes

Excessive soot loading in DPF (restricted filter)
Faulty or out-of-range DPF differential pressure sensor
Faulty exhaust gas temperature (EGT) sensors upstream or downstream of DPF
Leaking or damaged exhaust (upstream of DPF) or vacuum/exhaust leaks
EGR system fault or intake leak causing high soot production
Over-fueling (worn injectors, incorrect injector timing, high fuel pressure)

Symptoms

MIL/CEL (amber engine light) illuminated
Frequent active/forced DPF regenerations or unexpected regen events
Noticeable increase in fuel consumption
Reduced performance or intermittent power loss
Visible smoke or strong diesel smell from exhaust
Failed emissions test or DPF-related warnings/messages

What to check

Read freeze frame and history for conditions when code set (engine RPM, load, vehicle speed, coolant temp, regen count)
Scan for additional DTCs (EGR, injectors, sensors, communications)
Visual inspection: exhaust system, DPF for damage, wiring/connectors to sensors
Check DPF differential pressure sensor and EGT sensor operation with a scan tool
Confirm soot load, regen counts, and active regen events from dealer-level data or OEM scanner
Inspect for exhaust leaks upstream of the DPF and for intake/EGR leaks

Signal parameters

DPF differential pressure (kPa or mbar) — increases as soot accumulates; compare upstream vs downstream
Soot load or DPF soot mass (%) if available from scanner
Exhaust gas temperature upstream/downstream of DPF (°C) — used during regen
EGT sensor voltages/resistances (if applicable)
Engine RPM and engine load (%) during regen events
Fuel rail pressure (bar) and injector pulses/fueling rate

Diagnostic algorithm

Retrieve all codes, freeze frame and live data with a capable scan tool. Note regen counts and conditions when P243C set.
Check for related codes (EGR, injectors, EGT sensors, differential pressure sensor). Address any primary faults first.
Perform a visual inspection of DPF, exhaust for leaks or damage, and inspect sensor connectors and wiring for corrosion or breaks.
Monitor differential pressure sensor output at idle and under load. Compare upstream vs downstream pressures and look for expected rise with increased RPM/load.
Monitor exhaust temperatures upstream and downstream during normal operation and during a controlled / safe forced regen. Upstream should be significantly hotter during a regen.
Check soot load or DPF soot mass from the scan tool. High soot indicates filter restriction — consider cleaning or replacement per manufacturer procedure.
Inspect EGR system operation and intake for leaks that may cause excess soot production. Verify turbocharger operation and boost control.
Verify fuel system (pressure, injector balance) to rule out over-fueling or leaking injectors contributing to excess soot.
If sensors are out of expected range or intermittent, test/replace the differential pressure or EGT sensors and clear codes. Re-run tests.
If DPF is heavily restricted and cleaning is ineffective, consider DPF regeneration/cleaning or replacement following OEM procedures. After repairs, reset codes and perform road test/forced regen where safe to confirm the issue is resolved.
If problem persists, check PCM software updates and consult OEM technical resources/TSBs.

Likely causes

High soot load in the DPF (most common)
Bad or drifting differential pressure sensor on Bank 2
Damaged/incorrect exhaust temperature sensor readings
Exhaust leak upstream of DPF affecting sensor readings
EGR or fuel system issue increasing soot production

Fault status

⚠️ Status

PCM recorded abnormal particulate filter regeneration frequency for Bank 2 (P243C). MIL may be on. Inspect DPF system, sensors, and related fuel/EGR systems.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.5-4.0 hours