P2CE9

Code

Generic P — Powertrain

Particulate Filter Pressure Sensor C Circuit Intermittent/Erratic

Brand: Generic

Type: P — Powertrain

Views: UK: 22 EN: 47 RU: 29

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Page language: EN

Causes

Intermittent/open/short in sensor C wiring or connector
Corroded, loose or damaged connector pins
Faulty particulate filter pressure sensor C
Intermittent ECU input or ground connection
Electromagnetic interference or high resistance in reference/ground
Contamination (oil/water) in sensor or connector

Symptoms

MIL (Check Engine) lamp illuminated intermittently
Erratic or intermittent DPF regeneration behavior
Unexpected DPF pressure readings or DPF regen warnings
Loss of power or limp mode in some vehicles if ECU applies protective strategy
No obvious drivability symptoms in some cases—code only

What to check

Read freeze frame and live data to capture conditions when the code set
Check for other stored codes related to DPF, MAP or supply voltage/ground
Visually inspect sensor C, connector, and wiring for damage, corrosion, contamination or loose pins
Wiggle test wiring and connectors while watching live sensor data for intermittent changes
Backprobe connector and measure reference voltage, signal voltage and ground
Compare sensor C live signal to other pressure sensors (if present) or to expected values

Signal parameters

Reference (supply) voltage: typically 5.0 V (check manufacturer spec)
Signal output: typically ~0.2–4.8 V across sensor range (0 to full differential pressure) — confirm vehicle spec
Sensor impedance/resistance: manufacturer-specific; expect stable reading at measured pressure
Change in signal should be smooth and repeatable with engine speed/load or known pressure change
No rapid spikes, dropouts or floating values when sensor is connected and system running

Diagnostic algorithm

Retrieve freeze frame data and any associated codes. Note engine temperature, load, speed and DPF conditions when the fault occurred.
Inspect sensor C connector and wiring visually for damage, corrosion, broken strands, pin lift, or contamination. Repair/replace damaged harness or connector as required.
With ignition ON (engine off), backprobe the sensor connector: confirm reference voltage (usually 5 V), good ground, and an initial signal voltage. Record values.
Start engine and monitor live signal voltage while varying engine speed or inducing small pressure changes (if safe). Look for erratic spikes, dropouts, or intermittent losses of signal.
Wiggle the wiring harness and connector while observing live data to reproduce the intermittent behavior. If the fault appears during wiggle, repair the wiring/connector.
If wiring and connectors check good, swap sensor C with a known-good same-type sensor (if available) or measure sensor resistance per manufacturer spec to confirm internal intermittent failure. Replace sensor if faulty.
Check continuity between sensor ground and ECU ground and verify low resistance. Repair any poor grounds.
Inspect ECU connector and terminal condition if wiring and sensor are good. Some intermittent faults originate in ECU connector or ECU pins—repair as needed.
After repairs, clear codes and perform road test/regeneration under the same conditions to confirm the fault does not return.
If intermittent persists and wiring, sensor and grounding are verified, consult manufacturer data for ECU diagnostics or consider ECU repair/replacement.

Likely causes

Damaged or chafed wiring harness to sensor C (pinch, abrasion)
Poor connector mating or corrosion at the sensor plug
Failed pressure sensor (intermittent internal fault)
Poor ground at sensor or ECU chassis ground
Loose or intermittent ECU connector
Intermittent short to battery or ignition feed affecting reference voltage

Fault status

⚠️ Status

Intermittent/erratic signal detected from particulate filter pressure sensor C circuit. The control module observed signal values outside expected behavior (dropouts, spikes, or unstable readings) but not a permanent open/short. Code may be stored as intermittent and can return if the fault recurs.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-3.0 hours