P272B

Cylinder 14 Injector Circuit Low

P272B is a generic OBD-II powertrain diagnostic trouble code: Cylinder 14 Injector Circuit Low. It is logged by the engine control unit when the powertrain monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.

Code
P272B
Group
Powertrain
System
Powertrain
Severity
Warning (MIL on, possible limp mode)
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What P272B means

P272B is stored when the PCM detects that the voltage or current on the cylinder 14 fuel injector control circuit is lower than the expected threshold during the commanded injection event. This differs from an open circuit (P271E) in that the circuit is complete but the signal level is insufficient, typically because of excessive resistance in the circuit or a partially shorted driver path pulling the line low.

The injector driver circuit operates at precise current levels to control solenoid actuation timing, which directly affects fuel quantity and injection timing. A low-circuit condition can cause the injector to open too slowly, not fully, or erratically, leading to incomplete combustion, rough running, and elevated emissions from the affected cylinder.

Diagnosis should include checking for high-resistance connections, corroded terminals, and undersized or damaged wiring. A parasitic load introduced by a chafed wire partially grounded to the chassis can also produce a low-circuit fault. Systematic harness inspection combined with injector resistance measurement will identify most root causes without requiring component replacement.

Common causes

Most-frequently reported root causes when P272B is logged.

  • 1
    High resistance in the cylinder 14 injector wiring harness due to corrosion or damaged conductors.
  • 2
    Corroded or high-resistance connector terminals at the cylinder 14 injector.
  • 3
    Partial short to ground in the injector control wiring reducing available drive voltage.
  • 4
    Injector solenoid winding with elevated internal resistance.
  • 5
    Failing PCM injector driver outputting insufficient current.
  • 6
    Loose or improperly seated injector connector causing intermittent high resistance.
  • 7
    Water intrusion into the wiring harness causing resistive corrosion.

Symptoms drivers notice

MIL illuminated.
Rough idle or misfire sensations from the affected cylinder.
Possible companion cylinder-specific misfire DTC.
Reduced power output proportional to cylinder count.
Increased fuel consumption due to inefficient combustion in the affected cylinder.

How to diagnose P272B

A typical diagnostic flow when this code is present.

  1. 1
    Scan for all DTCs and freeze frame data; document any companion misfire or injection fault codes.
  2. 2
    Inspect the cylinder 14 injector connector and harness routing for corrosion, chafing, or damaged insulation.
  3. 3
    Measure the injector solenoid resistance at the injector connector and compare to specification.
  4. 4
    Check circuit resistance from the PCM injector driver pin to the injector connector with the harness disconnected.
  5. 5
    Perform a voltage-drop test across each connector in the circuit with the circuit energized to identify high-resistance joints.
  6. 6
    Use a lab scope to observe injector current waveform during operation and compare peak and hold levels to expected values.
  7. 7
    Repair any wiring or connector faults found; retest before considering PCM replacement.

Related powertrain codes

Frequently asked questions

What is the difference between P272B (circuit low) and P271E (circuit open)?

An open circuit means no current path exists at all. A low circuit means the path exists but voltage or current is below the acceptable minimum, often due to high resistance rather than a complete break.

Can corrosion inside a connector cause this code?

Yes. Corrosion at connector terminals significantly increases resistance, which drops the voltage available to the solenoid and can set a low-circuit fault.

Do I need to replace the injector if this code is set?

Not necessarily. First verify wiring and connector integrity. The injector itself is only a suspect if its solenoid resistance is outside specification.

Can this code appear intermittently?

Yes. Loose connectors or chafed wiring that makes intermittent contact can cause the code to appear and disappear with vibration or temperature changes.

Disabling P272B in software

RaceTune can permanently disable P272B — 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 P272B 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 EDC17C56 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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