P23BF

Cylinder 3 Injector Circuit High

P23BF is a generic OBD-II powertrain diagnostic trouble code: Cylinder 3 Injector Circuit High. 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
P23BF
Group
Powertrain
System
Powertrain
Severity
Warning (MIL on, possible limp mode)
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What P23BF means

P23BF indicates that the PCM has detected a high-circuit condition in the fuel injector control circuit for cylinder 3. The monitoring strategy compares actual driver feedback to expected values during each injection event; a consistently elevated reading triggers fault storage and MIL illumination.

A short to battery voltage is the most likely cause, either in the injector harness, the connector, or in rare cases within a failed injector solenoid. When this fault is active, the PCM may deactivate the cylinder 3 injector as a protection measure, causing a cylinder-specific misfire. Extended operation in this state can overheat the three-way catalyst with unburned oxygen and hydrocarbons.

Systematic electrical diagnosis starting at the connector and working toward the PCM is the safest diagnostic path. Avoid replacing the injector without first confirming the solenoid resistance is out of specification, as most P23BF faults are wiring-related rather than injector-related.

Common causes

Most-frequently reported root causes when P23BF is logged.

  • 1
    Short to battery voltage on the cylinder 3 injector control wire.
  • 2
    Wiring insulation breach where the harness contacts the engine block or a hot surface.
  • 3
    Internally shorted injector coil on cylinder 3.
  • 4
    Corroded or damaged connector terminal creating an unintended high-voltage path.
  • 5
    PCM internal driver failure outputting an erroneous voltage level.
  • 6
    Harness damage from rodent activity resulting in bare wire contact with voltage sources.
  • 7
    Poorly executed prior wiring repair introducing a high-side short.

Symptoms drivers notice

MIL illuminated and P23BF in memory.
Misfire detected on cylinder 3.
Rough running or vibration at idle.
Possible power reduction or limp-mode condition.
Fuel odor or elevated hydrocarbon emissions.

How to diagnose P23BF

A typical diagnostic flow when this code is present.

  1. 1
    Retrieve all DTCs and freeze-frame data before clearing or testing.
  2. 2
    Perform a visual inspection of the cylinder 3 injector harness for chafing, melting, or contact with high-voltage sources.
  3. 3
    Check injector connector terminal condition for corrosion, spread pins, or moisture intrusion.
  4. 4
    Measure injector coil resistance; compare against specification.
  5. 5
    With key on, engine off, verify control-side pin voltage is at or near zero before PCM energizes the circuit.
  6. 6
    Trace the control wire to the PCM using a wiring diagram, testing for shorts to voltage at intermediate connectors.
  7. 7
    Repair any identified wiring fault, clear codes, and verify the repair with a monitored drive cycle.

Related powertrain codes

Frequently asked questions

Can P23BF cause a no-start condition?

Unlikely on a multi-cylinder engine; the remaining cylinders can still fire. However, a severe wiring fault could potentially affect adjacent injector circuits.

How do I tell if the injector itself is faulty vs. the wiring?

Measure the injector coil resistance at the connector with the harness unplugged. A reading outside the manufacturer specification indicates a faulty injector solenoid.

Will P23BF cause the vehicle to fail an emissions test?

Yes. An active MIL will cause an automatic fail in most OBD-II emissions programs.

Should companion misfire codes change my diagnosis approach?

A companion P0303 alongside P23BF confirms the electrical fault is affecting cylinder 3 firing. It does not change the electrical diagnosis path but confirms the operational impact.

Disabling P23BF in software

RaceTune can permanently disable P23BF — 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.

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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