P0192 Fuel Rail Pressure Sensor A Circuit Low — Causes & Fix
Updated for 2026 diagnostics & repair guidance
P0192 at a Glance
What it means
The rail pressure sensor signal is stuck below its valid range.
Most common cause
Rail pressure sensor fault
Severity
Moderate to serious — rail-pressure faults cause power loss and non-starts.
Can you drive?
Short distances in limp mode only. Diagnose promptly.
Typical repair cost
£40-£150 for sensor/regulator work; £100-£350 per injector where back-leak is the cause.
What Does P0192 Mean?
P0192 means the rail-pressure sensor signal has dropped below its plausible window — a short to ground, poor connector contact or a failed sensor element. The ECU distrusts the reading and limits fuelling until the circuit tests clean.
Common Causes
Injector-Related Causes
Genuine pressure instability
Excessive injector back-leak or a failing pump makes the real pressure so unstable the sensor reading is flagged.
Other Possible Causes
Rail pressure sensor fault
The sensor's output drifts or fails, so the ECU no longer trusts the pressure reading.
Sensor circuit wiring fault
Open, short or corroded wiring between the sensor and ECU skews the measured signal.
Symptoms Drivers Notice
- Loss of power / limp mode
- Hard or extended starting, especially when warm
- Engine cutting out or refusing to restart
- Engine management light on
Vehicles Commonly Affected
Can You Still Drive with P0192?
Limp mode usually allows a short, gentle drive but rail-pressure faults can cause sudden cut-outs. Do not ignore a hot-restart failure — it typically worsens quickly.
How Mechanics Diagnose P0192
- 1
Compare requested vs actual rail pressure
Check live data at idle, under load and while cranking.
- 2
Run an injector leak-off test
Excessive back-leak return identifies leaking injectors.
- 3
Test the regulator / control valve
Check the valve's response and inspect its wiring circuit.
- 4
Check the low-pressure supply
Inspect the lift pump, filter and pipework before condemning high-pressure parts.
Repair Solutions & Costs
Replace leaking injectors
Fit bench-tested remanufactured units and code them to the ECU.
Replace the sensor or control valve
Replace the rail-pressure sensor or control valve where testing isolates it.
Repair control-circuit wiring
Repair wiring or connector faults found on the control circuit.
Replacing injectors? Browse our remanufactured diesel injectors, reconditioned injectors or refurbished diesel injectors — all bench-tested with a 12-month warranty.
When Injector Replacement Is Required
When the leak-off test shows one or more injectors returning well above the others, those injectors are the cause of the pressure loss and must be replaced — regulators and sensors cannot compensate for internal injector leakage.
Compatible Remanufactured Injectors
OEM bench-tested injectors for engines affected by P0192 — verified pricing, 12-month warranty, free UK delivery.
Delphi A6510704987
Remanufactured Delphi 28272472DNR diesel injector for Mercedes-Benz 2.1 CDI OM651 engines. Direct-fit replacement for C-Class, E-Class, CLA, GLA, GLK, Vito, V-Class, Sprinter and SLK applications. Cross-references A6510704987, A6510702387, HRD351, 28272472. OEM-tested and calibrated with full flow and leak-back verification. Includes 12-month unlimited-mileage warranty. Supplied as an exchange unit — return your old injector within 30 days.
Fits: OM651, OM651.911, OM651.924, OM651.925
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Bosch 0445110613
BMW 2.0d B47 Remanufactured Common Rail Injector
Fits: B47, B47C20A, B47D20, B47D20A
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Bosch 13538514148
2.0L Diesel Remanufactured Solenoid Injector (BMW B47)
Fits: B47, B47C20A, B47D20, B47D20A
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Delphi 28307309
Delphi remanufactured diesel injector for Mercedes OM651 applications. OEM tested and calibrated on CR318 PRO test bench. 12-month warranty included. Free UK delivery. Suitable for professional garage use. Exchange unit — return your old injector within 30 days.
Fits: OM651.955, OM651.956, OM651.957, OM651.958
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Delphi 28388960
Remanufactured Delphi 28388960 diesel injector for Ford 2.0 TDCi and Peugeot/Citroen 2.0 HDi/BlueHDi DW10 engines. Direct replacement for Ford Mondeo, Kuga, S-Max, Galaxy, Focus, C-Max, Edge and Peugeot 308, 508, 3008, 5008, Expert, Citroen C4, C5, DS4, DS5, Jumpy, Jumper applications. Cross-references 28602948, 9674984080, DS7Q9F593BA, HRD360. OEM-tested and calibrated with full flow and leak-back verification. Includes 12-month unlimited-mileage warranty. Supplied as an exchange unit — return your old injector within 30 days.
Fits: DW10C, DW10CB, DW10CT, DW10CTED4
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Bosch 0445110601
BMW 2.0d N47 Remanufactured Common Rail Injector
Fits: N47C20A, N47D20A, N47D20C
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Bosch 0445110616
BMW 2.0L / 3.0L Diesel Remanufactured Common-Rail Injector (N47/N57)
Fits: N47D20B, N47D20C, N47D20O1
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Siemens VDO / Continental 5WS40156Z
DW10 / 2.0 HDi / 2.0 TDCi / D4204T Remanufactured Common Rail Injector
Fits: DW10CB, DW10CTED4
View injectorCompatible Injector Part Numbers
6 injectors compatible with engines affected by P0192.
Cross Reference Numbers
OEM and alternative part numbers for injectors affected by P0192.
Affected Vehicle & Engine Combinations
Need a Replacement Injector?
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Order before 2pm for next working day delivery (UK mainland). Call us on 020 3355 6581.
Engine-Specific Guides
Frequently Asked Questions
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Fault Codes
Why It Happens
Common-rail injectors live at extreme pressures with clearances measured in microns. Fuel quality, heat cycles and mileage wear the internal control valve and nozzle: back-leak rises, spray patterns deteriorate and delivery drifts from calibration. Most 'engine' complaints on high-mileage diesels trace back to this gradual injector wear.
Professional Diagnosis
Workshops follow a fixed order: scan for codes and freeze-frame data, compare requested vs actual rail pressure on live data, read cylinder balance corrections, then run a comparative leak-off test. That sequence identifies the faulty injector without guesswork — and prevents needlessly replacing pumps, sensors or the wrong injector.
Typical Workshop Findings
The most frequent findings are: one injector returning several times the leak-off volume of its neighbours; carbon build-up from a failed copper washer; corroded injector connectors; and missing injector coding after a previous repair. Genuine high-pressure pump failures are rarer than back-leak faults that mimic them.
When to Replace Injectors
Replace when testing proves internal wear: leak-off clearly above the other injectors, balance corrections at their limits, or a failed bench test. Cleaning and additives cannot restore worn internal clearances. Bench-tested remanufactured injectors restore original calibration at a fraction of the new price — always coded to the ECU where the engine requires it.
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