The fuel rail pressure sensor is reading too high — common on common-rail diesels.
P0193 — also written PO193, P 0193, 0193 — is the OBD-II code for fuel rail pressure sensor high input. Same code, same fix: this page covers every spelling of it.
Fuel rail pressure sensor 'A' circuit — high input. The ECU sees an unrealistically high voltage from the fuel-rail pressure sensor, which usually means a sensor fault, a wiring short-to-power, or occasionally a genuine over-pressure spike from a stuck regulator. Common on direct-injection petrol and common-rail diesel systems.
P0193 is a fuel & air fault code, typically costing £120–£700 to put right in a UK garage.
What P0193 actually feels like to drive
- Cranks but won't start when hot
- Sudden power loss / limp mode with EML
- Occasional cut-out under acceleration
- Rail-pressure live data reads maxed-out (5V pegged) or wildly inconsistent
- Paired codes: P0087 (rail pressure too low), P0088 (too high), P0191 (range/perf), P0192 (low input)
What causes P0193?
- Failed pressure sensor
- Wiring short
- Stuck pressure regulator
UK vehicles that throw P0193 most often
- Ford Focus / Kuga / Mondeo 2.0 TDCi (Delphi DFP1)
- VW Golf / Passat / Audi A3 / A4 2.0 TDI (CR)
- Vauxhall Astra J / Insignia 1.7/2.0 CDTi (Denso/Bosch)
- BMW 320d / 520d N47/B47
- Ford EcoBoost 1.0 / 1.6 / 2.0 (petrol GDI rail sensor)
- Peugeot 308 / Citroën C4 1.6/2.0 HDi
How P0193 is fixed
- Replace rail pressure sensor
- Replace pressure regulator
- Repair wiring
The P0193 misdiagnosis that wastes money
The sensor is the odds-on favourite (£45–£120 part on most cars) but don't fit one without three checks. One — inspect the connector for water/salt corrosion; on Ford TDCi the connector sits in the V of the engine and copes with a lot of heat, and pin fret is common. Two — back-probe the 5V reference and ground; if the reference is missing or dropping you've got an ECM-side issue and a new sensor will read the same. Three — cross-reference with rail-pressure live data. If the actual rail pressure tracks commanded rail pressure fine but the sensor reads 5V pegged high, the sensor's dead; if actual can't hit commanded, you've got a pump/regulator problem masquerading as a sensor.
What a UK garage should charge for P0193
Diagnostic + live rail-pressure trace £60–£110, rail-pressure sensor £85–£220 fitted (accessible), connector/loom repair £60–£180, fuel-pressure regulator (DRV/MPROP) £150–£320 fitted, HP pump replacement (if underlying) £850–£1,800. Labour From £70/hr.
P0193 repair cost in the UK
Most P0193 repairs land between £120–£700 including parts and labour. The spread is wide because the cheap fix (a sensor, a hose, a leak) and the expensive fix (a major component) throw the same code — which is why a proper diagnosis before parts are bought saves the most money.
Bob's tip on P0193
On any common-rail diesel do NOT unscrew the rail sensor while the rail is pressurised — even engine-off there's residual pressure that can inject fuel into your skin. Depressurise, wait 30 minutes minimum. On Ford 2.0 TDCi the Delphi sensor has a known-failure part number — buy Delphi/OE only, aftermarket eBay parts often fail within weeks. On Ford EcoBoost (petrol GDI) the rail sensor sits on the direct-injection rail at 200-bar+; use only OE Bosch sensors and torque to spec, over-tightening cracks the sensor body. <a href="/ask-a-mechanic-uk?code=P0193">Ask Bob about your P0193</a> for £14.99 with make, model, mileage and any paired P0087/P0088 codes — you'll know whether it's a £90 sensor, a £250 regulator, or the start of a pump job.
Can you drive with P0193?
Limp mode likely.
Urgency: high.