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DTC codes / P2Exx · Hybrid propulsion / P2E57

P2E57Exhaust Pressure Sensor C Circuit High

P2E57 indicates that the powertrain control module (PCM) has detected an abnormally high voltage on the signal circuit of the exhaust pressure sensor, often referred to as sensor C. This sensor measures the pressure in the exhaust system, typically for diesel particulate filter (DPF) monitoring, and the high voltage suggests a short to voltage or an open circuit in the sensor wiring or connector.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaHybrid propulsion

Symptoms you may notice

  • Illumination of the check engine light (malfunction indicator lamp, MIL).
  • Often no noticeable symptoms besides the warning light.
  • Reduced engine performance or power, especially under load.
  • Poor fuel economy due to incorrect pressure readings affecting fuel delivery.
  • Possible activation of limp mode (reduced power) in some vehicles.
  • In rare cases, excessive black smoke from the exhaust if the sensor fault affects DPF regeneration.

Common causes, most likely first

  1. Faulty exhaust pressure sensor C (internal short to voltage).
  2. Damaged or corroded electrical connector at the sensor.
  3. Short to voltage in the signal circuit wiring (e.g., chafed wire touching a power wire).
  4. Open circuit in the sensor ground circuit, causing the signal voltage to float high.
  5. Water intrusion or contamination in the sensor or connector.
  6. PCM internal fault (rare).

How to diagnose and fix it

  1. Perform a visual inspection of the sensor, connector, and wiring for damage, corrosion, or loose connections.
  2. Use a scan tool to check live data for the exhaust pressure sensor reading and compare with key-on, engine-off (KOEO) and engine-running values.
  3. Measure reference voltage (typically 5V) and ground at the sensor connector with a digital multimeter (DMM) to verify power and ground integrity.
  4. Check the signal circuit for a short to voltage by measuring voltage with the sensor disconnected and the key on; should be near 0V if no short.
  5. Inspect the wiring harness for chafing or damage where it routes near hot or moving components.
  6. If wiring and connectors are good, replace the exhaust pressure sensor C.
  7. Clear the diagnostic trouble codes (DTCs) and verify the repair by test-driving the vehicle and ensuring the code does not return.

Exhaust Pressure Sensor C Circuit High Pitfalls

  • A common mistake is replacing the sensor without checking the ground circuit; a poor ground can cause the signal voltage to read high, mimicking a sensor failure.
  • The exhaust pressure sensor is often used for DPF regeneration, so a faulty reading can lead to frequent or failed regenerations, causing DPF clogging over time.
  • On some vehicles, the sensor is part of a combined sensor assembly (e.g., differential pressure sensor), and replacing just one sensor may not be possible.
  • Water intrusion into the sensor connector is a frequent cause, especially in vehicles driven in wet or muddy conditions, and can cause intermittent high voltage codes.
  • The code may set intermittently due to vibration or temperature changes affecting a marginal connection, so always wiggle-test the harness while monitoring live data.

Can I keep driving with P2E57?

The vehicle is generally safe to drive with this code, but avoid heavy loads or sustained high-speed driving until repaired, as incorrect pressure readings can affect DPF regeneration and lead to more costly damage over time. If the engine enters limp mode, seek repair promptly.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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