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.
P0193 on specific UK makes
P0193: quick answers
Is P0193 serious?
It can be. On most diesels the engine computer goes into limp mode to protect the injection system, and some cars won't restart until it's fixed. Sort it quickly.
Can I drive with P0193?
Only gently and only to get it looked at. Limp mode limits power, which is risky when you're overtaking or joining a motorway.
How much does P0193 cost to fix in the UK?
Typically £120–£700. A rail pressure sensor fitted is often £150–£450. Always check the wiring plug first, because a corroded pin gives exactly the same code.
Will P0193 fail an MOT?
If P0193 has the engine warning light on when the car goes in, yes — an illuminated engine management light is an MOT failure. Clearing the code the morning of the test doesn't work either: the readiness monitors reset and the tester can see it. Fix the cause, drive the car for a few days, then book the test.