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P0295 — Cylinder 12 Injector Circuit High

Generic OBD-II · all makesPowertrain (engine & transmission)

OBD-II code P0295 indicates that the engine control module (PCM/ECM) has detected an abnormally high voltage in the fuel injector circuit for cylinder 12. This typically suggests an electrical issue, such as a short to power or an open circuit, rather than a mechanical injector failure.

Symptoms

What causes it — most likely first

1. Faulty fuel injector (internal short or open circuit)

The injector itself may have an internal short to power or an open winding, causing excessive voltage in the circuit.

2. Damaged or chafed injector wiring harness

Wiring between the PCM and injector may be shorted to power, grounded, or broken due to wear, heat, or physical damage.

3. Poor electrical connection at injector or PCM

Corrosion, loose pins, or bent terminals in the injector connector or PCM harness can cause high resistance or intermittent high-voltage readings.

4. Faulty PCM injector driver circuit

While rare, the PCM’s internal driver circuit for the injector could fail, causing incorrect voltage signals. This is uncommon and should only be considered after all other causes are ruled out.

How it's diagnosed

  1. Retrieve and confirm the code using an OBD-II scanner, checking for related misfire or injector codes (e.g., P030X, P020X).
  2. Inspect the wiring harness and connector for cylinder 12’s injector for damage, corrosion, or loose connections. Repair as needed.
  3. Measure the resistance of the injector (compare to manufacturer specifications) and check for shorts to power or ground using a multimeter.
  4. Test the injector circuit voltage at the PCM connector with the key on/engine off (KOEO) to verify proper signal. Compare to expected values.
  5. Perform a wiggle test on the wiring harness while monitoring live data to check for intermittent faults.
  6. If all electrical checks pass, consider swapping the injector with a known-good one (e.g., from another cylinder) to isolate the issue.

Code facts & related codes

SystemPowertrain (engine & transmission)
StandardizationSAE generic — identical on every make

Frequently asked

Is the PCM usually the cause of P0295?

No. While the PCM controls the injector circuit, it is rarely the root cause of P0295. Most cases stem from wiring issues, connector problems, or a faulty injector. PCM failure should only be suspected after all other possibilities are exhausted.

Can I drive with a P0295 code?

Driving with this code may cause engine misfires, reduced performance, or potential catalytic converter damage due to unburned fuel. It’s best to diagnose and repair the issue promptly.

Why does my scanner show P0295 but no misfire?

P0295 is an electrical code, not a misfire code. The PCM may detect the high-voltage condition before a misfire occurs, or the misfire may be intermittent and not logged yet.

Do I need to replace the injector if I get P0295?

Not necessarily. The issue could be in the wiring, connectors, or PCM. Always perform electrical tests to isolate the fault before replacing components.