OBD-II Code · Fuel & Air
P0294
Cylinder 12 Injector Circuit Low
Severity
high
Left alone, this one tends to take other parts with it.
Can you drive it
Not for long
Driving on this one risks further damage. Get it to a shop rather than carrying on with it.
Indicative cost (USD)
$200–$2,800
Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
V12-only · cyl 12 injector shorted (rearmost on bank 2).
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then work the likely-causes list in the order shown.
That order is what a shop checks first for this code — wiring and connections before the component they run to, because a connector costs nothing to inspect and is a common answer.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Misfire cyl 12
- Check engine light
Likely causes
- Shorted GDI injectorMost common
- IDM channel failure
- Harness damage
Read the full diagnostic procedureP0294 is V12-only and sets when the PCM detects the cylinder 12 injector circuit pulled low or shorted, where cyl 12 is typically the rearmost cylind…
P0294 is V12-only and sets when the PCM detects the cylinder 12 injector circuit pulled low or shorted, where cyl 12 is typically the rearmost cylinder on bank 2.
Cheapest first
- swap injector 12 with another cylinder on the same bank and clear codes.
- GDI solenoid windings on Mercedes M275/M279, BMW N74, Lamborghini L539, and modern Ferrari V12 should ohm 1.5 to 4 ohms cold; under 1 ohm indicates a shorted winding.
- Key-on engine-off, driver-side pin should be open to ground with injector unplugged; 0 ohms to chassis ground indicates a harness short.
- Pulse width at warm idle on these engines is typically 0.3 to 0.7 ms GDI, with cold-start enrichment widening to 1.2 to 1.8 ms briefly.
- Caveat: on Mercedes M275/M279 cylinder 12 access requires removing the rear intake plenum on most chassis (W221, W216, R230), so spend the time on connector pin-drag testing and IDM swap diagnostics before committing to teardown; the labor delta between a 10-minute IDM swap and an injector R&M is 4 to 6 hours.
Vehicle-specific patterns2003 to 2014 Mercedes-Benz M275/M279 V12 (S600, SL600, CL600, S65 AMG) has documented HDEV-series injector winding failures and IDM channel-specific…
- 2003to 2014 Mercedes-Benz M275/M279 V12 (S600, SL600, CL600, S65 AMG) has documented HDEV-series injector winding failures and IDM channel-specific faults that present as cylinder 11/12 codes first;
- 2009to 2015 BMW 760i/760Li N74 V12 has TSB-documented injector driver module replacement procedures (BMW SI B12 09 13);
- 2002to 2010 Ferrari 612 Scaglietti and 599 GTB F133 V12 use port-injected solenoids that fail at the connector seal allowing moisture intrusion.
Estimated repair$200 to $2,800.
Look up another code
P0294 — frequently asked
What does a P0294 code mean?
V12-only · cyl 12 injector shorted (rearmost on bank 2).
What causes a P0294 code?
Common causes: Shorted GDI injector; IDM channel failure; Harness damage.
What are the symptoms of a P0294 code?
Typical symptoms: Misfire cyl 12; Check engine light.
Is it safe to drive with a P0294 code?
Not for long. Driving on this one risks further damage. Get it to a shop rather than carrying on with it. Estimated repair: $200-$2,800.
How do I diagnose a P0294 code?
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed. 1. Note every code that is set, not just this one. 2. Read the freeze frame — the conditions the fault was recorded under. 3. Confirm the fault is current rather than history. 4. Then work the likely-causes list in the order shown.
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