Exhaust Pressure Sensor Intermittent

Possible causes

• CommonSensing hoses blocked with soot - the most common fault on a diesel
• CommonSplit, perished or disconnected sensing hose
• CommonFailed exhaust pressure sensor
• CommonCorroded connector or wiring damaged by exhaust heat
• CommonBlocked particulate filter, so the pressure genuinely is high
• PossibleLoss of reference voltage or earth

What you might notice

• Reduced power or limp mode
• Particulate filter warning
• Regeneration running too often or not at all
• Excessive smoke
• Worse fuel economy
• Check engine light on

What to check, in order

1. Check the sensing hoses first. On a diesel these run from the exhaust to the sensor and block solid with soot, which is by far the most common cause and costs nothing but time to clear.
2. Compare the reported pressure with atmospheric on a stationary engine - they should be close. A reading well away from that with the engine off proves the sensor or its hoses wrong.
3. Inspect the connector for corrosion and the wiring for heat damage.
4. Read all codes. Particulate filter codes alongside this one mean the pressure may be genuinely high and the filter is the problem.
5. Check the reference voltage and earth at the sensor.