P0201 Injector Circuit Malfunction (Cylinder 1) — Causes & Fix
Updated for 2026 diagnostics & repair guidance
P0201 at a Glance
What it means
The ECU has detected a fault in the fuel injector electrical circuit for cylinder 1.
Most common cause
Faulty injector, wiring damage, or ECU driver fault.
Severity
Moderate to serious — causes misfire on cylinder 1.
Can you drive?
Short distances only. Prolonged driving risks DPF and catalytic converter damage.
Typical repair cost
£100-£350 for injector replacement; £40-£100 for wiring repair.
What Does P0201 Mean?
P0201 is a generic OBD-II code indicating the Engine Control Unit (ECU) has detected an electrical fault in the fuel injector circuit for cylinder 1. This could be an open circuit, short circuit, or incorrect resistance in the injector solenoid or its wiring. The ECU may disable fuel delivery to cylinder 1, causing the engine to run on three cylinders.
Common Causes
Injector-Related Causes
Failed injector solenoid
The electromagnetic coil inside the injector has failed, preventing it from opening. This is the most common cause on vehicles over 80,000 miles.
Incorrect injector coding
If an injector was recently replaced without coding, the ECU may flag a circuit fault due to mismatched parameters.
Other Possible Causes
Damaged wiring to injector
The wiring harness between the ECU and injector is damaged, corroded, or broken. Common in vehicles exposed to salt spray or engine bay heat.
Corroded injector connector
The electrical connector on top of the injector has corroded internally, creating high resistance. Often caused by water ingress.
ECU injector driver fault
The transistor in the ECU that drives the injector has failed. Less common but requires ECU repair or replacement.
Symptoms Drivers Notice
- Engine misfires and runs rough, especially at idle
- Noticeable vibration through the steering wheel and cabin
- Loss of power during acceleration
- Engine management light illuminated (steady or flashing)
- Increased fuel consumption (10-20%)
- White or black smoke from exhaust
Vehicles Commonly Affected
Can You Still Drive with P0201?
Driving short distances at low load is generally safe. However, prolonged driving on three cylinders can cause: unburnt fuel contaminating the DPF, increased load on the catalytic converter, oil dilution from fuel washing past the piston rings, and secondary damage to the turbocharger. We recommend diagnosis within 48 hours.
How Mechanics Diagnose P0201
- 1
Read and confirm fault codes
Use an OBD scanner to confirm P0201 and check for additional codes (e.g., P0300 general misfire).
- 2
Inspect wiring and connector
Visually inspect the injector connector and wiring harness to cylinder 1 for damage, corrosion, or loose connections.
- 3
Measure injector resistance
Disconnect the injector and measure resistance across the solenoid pins. Compare to spec (typically 0.3-1.2 ohms for solenoid injectors).
- 4
Perform leak-off test
If electrical tests pass, perform a leak-off test to check for mechanical injector failure.
- 5
Swap test (optional)
Swap the cylinder 1 injector with another cylinder. If the code follows the injector, it confirms injector failure.
Repair Solutions & Costs
Replace the injector
If the injector solenoid has failed, replacement is the only fix. Remanufactured injectors are a cost-effective, OEM-spec option.
Repair the wiring
If the wiring is damaged, repair or replace the affected section. Soldering and heat-shrinking is the professional approach.
Clean or replace connector
Corroded connectors can sometimes be cleaned with electrical contact cleaner. Severely corroded connectors should be replaced.
ECU repair
If the ECU injector driver has failed, specialist ECU repair is needed. This is uncommon but possible on high-mileage vehicles.
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
Injector replacement is required when: the solenoid resistance is out of spec, the leak-off test shows excessive return flow, the swap test confirms the fault follows the injector, or the injector has visible signs of damage (cracked body, burnt connector).
Compatible Remanufactured Injectors
OEM bench-tested injectors for engines affected by P0201 — verified pricing, 12-month warranty, free UK delivery.
Siemens VDO / Continental A2C9303500080
2.0L EcoBlue Remanufactured Common Rail Injector (Ford Transit / Transit Custom / Tourneo Custom)
Fits: ADBC, ADBD, ADBE, BC2X
View injector
Siemens VDO / Continental 5WS40156Z
DW10 / 2.0 HDi / 2.0 TDCi / D4204T Remanufactured Common Rail Injector
Fits: AZWA, AZWC, D4204T, D4204T2
View injector
Bosch 0445110369
VW/Audi 2.0 TDI (EA189/EA288) Remanufactured Common Rail Injector
Fits: CDLC, CFFA, CFFB, CFFD
View injector
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: AZBA, AZBC, DW10C, DW10CB
View injector
Siemens VDO / Continental A2C59511606
Siemens VDO / Continental A2C59511606 remanufactured diesel injector for Renault, Nissan and Dacia 1.5 dCi K9K engines. OEM tested and calibrated on CR318 PRO test bench. 12-month warranty included. Free UK delivery. Exchange unit — return your old injector within 30 days.
Fits: K9K278, K9K282, K9K288, K9K292
View injector
Bosch 0445110955
PSA/Ford 1.5 EcoBlue/BlueHDi Remanufactured Common Rail Injector
Fits: BEGA, D15DT, D15DTH, YHR
View injector
Bosch 0445110351
1.3L Multijet/JTD/TDCi/HDi/DDiS Remanufactured Common Rail Injector
Fits: 1.3JDTM, 1.3JTD, 1.3SDE, 169A1.000
View injector
Bosch 0445110470
VW/Audi 2.0 TDI (EA288 Gen2) Remanufactured Common Rail Injector
Fits: CNHA, CNHC, CRGB, CUNA
View injectorCompatible Injector Part Numbers
4 injectors compatible with engines affected by P0201.
Cross Reference Numbers
OEM and alternative part numbers for injectors affected by P0201.
Affected Vehicle & Engine Combinations
Trusted Injector Families for These Engines
Verified remanufactured injector families fitted to engines documented to log P0201.
A2C9303500080
Siemens VDO / Continental · 2.0L EcoBlue
Engines: ADBC, ADBD, ADBE, BC2X, BCCC, BCCD
5WS40156Z
Siemens VDO / Continental · DW10 / 2.0 HDi / 2.0 TDCi / D4204T
Engines: AZWA, AZWC, D4204T, D4204T2, D4204T5, DW10BTED4
0445110369
Bosch · VW/Audi 2.0 TDI (EA189/EA288)
Engines: CDLC, CFFA, CFFB, CFFD, CFFE, CFGB
28388960
Delphi · 2.0L HDi
Engines: AZBA, AZBC, DW10C, DW10CB, DW10CT, DW10CTED4
A2C59511606
Siemens VDO / Continental · 1.5L dCi
Engines: K9K278, K9K282, K9K288, K9K292, K9K430, K9K728
0445110955
Bosch · PSA/Ford 1.5 EcoBlue/BlueHDi
Engines: BEGA, D15DT, D15DTH, YHR, YHV, YHW
Need a Replacement Injector?
UK-tested remanufactured injectors with 12-month warranty. Search by engine code or vehicle registration.
Need it fast? Same-day dispatch on in-stock injectors.
Order before 2pm for next working day delivery (UK mainland). Call us on 020 3355 6581.
Engine-Specific Guides
Mercedes OM651
Injector guide
BMW N47
Injector guide
BMW B47
Injector guide
Ford Transit 2.2 TDCi
Injector guide
PSA DW10C
Injector guide
VW CAYC
Injector guide
Mercedes OM646
Injector guide
BMW N57
Injector guide
Renault 1.5 dCi K9K
Injector guide
Renault / Nissan M9R
Injector guide
PSA / Ford 1.6 HDi DV6
Injector guide
Ford 2.0 TDCi TXDB
Injector guide
Frequently Asked Questions
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Fault Codes
Symptoms
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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