Powertrain, generic · Fuel and air metering

P0190 Fuel Rail Pressure Sensor A Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

The rail pressure sensor A measures the pressure in the high-pressure fuel rail of common-rail diesels and petrol direct-injection engines – a three-wire sensor with 5 V reference. P0190 is the general circuit code used when a manufacturer does not split low and high; GM and Ford use P0192/P0193 instead. Bosch EDC16 diesels (Saab/Opel 1.9) report P0190 with a fault type byte, and a Saab bulletin traces it to corrosion in the sensor connector, sometimes with no restart for up to 15 minutes. On a sensor fault the engine runs on a calculated pressure in limp mode – on Saab's 3.0 V6 diesel with at most 40 MPa rail pressure and 20 % pedal.

Likely causes

Connector corroded or water ingress at the rail pressure sensor
Rail pressure sensor faulty
Harness damaged (heat, chafing)
5 V reference disturbed

Symptoms

  • Check engine light on
  • Limp mode, loss of power
  • Stalling or no start (sometimes only after a waiting time)
  • Rough idle

Repair estimate

DifficultyMediumDIY possible
Parts and labour€80–500
Time0.5–2.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

What to check first

  1. Inspect connector
  2. Check reference voltage and ground
  3. Compare reading key-on engine-off

Parts involved

fuel rail pressure sensorsensor wiringsensor reference voltage

Related codes

P0191P0192P0193P0194P018AP0087

References: law.cornell.edu, saabwisonline.com, saabwisonline.com, fordservicecontent.com.