P0201

Injector Circuit Malfunction - Cylinder 1

P0201 is a generic OBD-II powertrain diagnostic trouble code: Injector Circuit Malfunction - Cylinder 1. It is logged by the engine control unit when the fuel/inj monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.

Code
P0201
Group
Powertrain
System
Fuel/Inj
Severity
high
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What P0201 means

P0201 is set when the Engine Control Module (ECM/PCM) detects an electrical fault in the fuel injector control circuit for cylinder 1. The ECM monitors the injector circuit by observing voltage behaviour: when it commands the injector solenoid open, it expects voltage to pull low (near 0 V); when it switches the injector off, it expects voltage to return to near battery voltage. A persistent deviation from these expected levels triggers P0201 and illuminates the malfunction indicator lamp (MIL).

The fuel injector is a solenoid-operated valve. When energised it opens a pintle to allow a precise metered pulse of pressurised fuel into the intake port or directly into the combustion chamber (depending on architecture). An open or short in the wiring, a failed solenoid coil inside the injector, or a damaged connector prevents the circuit from completing normally, meaning cylinder 1 may receive no fuel or inconsistent fuel delivery.

Because cylinder 1 is effectively disabled or unreliable, the engine runs on fewer cylinders than designed. This causes noticeable misfire, rough idle, power loss, and increased raw-fuel emissions. On direct-injection engines the unfired fuel can wash cylinder walls and dilute engine oil over time, so the fault should not be left unaddressed. Related misfire codes (P0301) often appear alongside P0201.

P0201 is one of a family of per-cylinder injector circuit codes (P0201–P0212). Diagnosis involves isolating whether the fault is in the injector itself, the wiring harness, the connector, or – as a last resort – the ECM driver circuit. Swapping the suspect injector to a known-good cylinder and observing whether the fault follows the part is the quickest mechanical test before committing to component replacement.

Common causes

Most-frequently reported root causes when P0201 is logged.

  • 1
    Faulty fuel injector (internal open circuit or failed solenoid coil)
  • 2
    Broken, chafed, or shorted wiring in the injector harness
  • 3
    Corroded or damaged injector electrical connector
  • 4
    Loose or backed-out terminal pins at the injector connector
  • 5
    Blown fuse or failed relay protecting the injector circuit
  • 6
    High injector resistance due to carbon deposits or age
  • 7
    Short to ground in the injector signal wire
  • 8
    ECM/PCM internal driver circuit failure (rare)

Symptoms drivers notice

Malfunction indicator lamp (MIL / check engine light) illuminated
Engine misfire on cylinder 1, often accompanied by P0301
Rough idle and engine vibration
Reduced power and hesitation under acceleration
Poor fuel economy
Hard starting or intermittent stalling
Strong fuel smell from exhaust (unburned fuel)

How to diagnose P0201

A typical diagnostic flow when this code is present.

  1. 1
    Connect a scan tool, record all stored codes and freeze-frame data, then clear and retest to confirm the fault is active.
  2. 2
    Visually inspect the cylinder 1 injector wiring harness and connector for chafing, heat damage, corrosion, or backed-out terminals.
  3. 3
    Check and replace any blown fuses or failed relays in the fuel injection circuit.
  4. 4
    Measure injector coil resistance with a digital multimeter and compare to the OEM specification (typically 12–16 Ω for port injectors, 0.5–3 Ω for GDI); replace injector if out of range.
  5. 5
    Use a noid light at the disconnected injector connector while cranking – a flashing light confirms the ECM is sending a control signal; no flash points to wiring or ECM.
  6. 6
    Test wiring continuity from the injector connector back to the ECM and check for shorts to ground or to battery voltage.
  7. 7
    Swap the cylinder 1 injector with a known-good cylinder, clear codes, and retest; if P0201 follows the injector to the new cylinder location, replace the injector.
  8. 8
    If all wiring, connectors, and the injector test good, inspect ECM connector integrity and test ECM driver output before considering ECM replacement.

Related powertrain codes

Frequently asked questions

Can I drive with a P0201 code?

Short distances are possible but not recommended. The affected cylinder delivers no or erratic fuel, causing misfire that stresses the catalytic converter and, on direct-injection engines, can cause fuel to wash the cylinder walls and dilute the engine oil. Address the fault promptly.

Will clearing the code make P0201 go away permanently?

No. Clearing the code removes the stored fault and turns off the MIL, but the underlying electrical fault remains. The ECM will re-detect the condition and re-set the code within one or two drive cycles if the root cause is not repaired.

Is P0201 always caused by a bad injector?

Not always. Wiring faults and corroded connectors are equally common and cheaper to repair. Always test the circuit before replacing the injector, because swapping a good injector into a faulty harness will not fix the problem.

Why does P0301 (cylinder 1 misfire) appear at the same time as P0201?

P0201 indicates an electrical fault in the injector control circuit; P0301 is the resulting combustion misfire. When the injector cannot open reliably, cylinder 1 misfires, so both codes are set simultaneously. Fixing P0201 typically resolves P0301 as well.

How much does it cost to fix P0201?

A wiring or connector repair is typically the least expensive fix. Injector replacement on a port-injection engine ranges widely depending on part and labour costs. ECM replacement is the most expensive outcome but also the rarest cause.

Disabling P0201 in software

RaceTune can permanently disable P0201 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.

Permanent
The monitor is disabled in the ECU itself — not just cleared. It cannot return.
Tailored to your file
Each patch is matched to your specific software version — never a one-size-fits-all file.
Reversible
The original file is always preserved. Reflash the stock to return the ECU to factory state.

ECUs with a P0201 disable in our catalogue

Confirmed coverage from our recipe database — we support many more families. Upload your file and our identifier will match it automatically.

  • Bosch MD1CP004 verified 1 software version

Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.

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