P0295 code: Cylinder 12 Injector Circuit High
P0295 means cylinder 12 Injector Circuit High. The code says where to look, not what failed — the fix depends on which cause your car actually has.
What P0295 means
The final code in the injector-circuit series, P0295 sets when the ECM detects above-expected voltage on the cylinder 12 injector control circuit — possible only on twelve-cylinder engines, where cylinder 12 typically sits at the back of one bank. High-side faults trace to a short to battery voltage in the harness or to added resistance: corroded connector pins, a degraded terminal, or an injector winding that has failed open. This monitor cannot see fuel flow, so the code definitively separates electrical faults from a mechanically clogged injector, which would misfire without tripping it. On a V12 the practical diagnostic advantage is redundancy — eleven identical circuits to compare against — so a resistance check and connector inspection at cylinder 12 usually finds the fault quickly. Related codes are P0212 (cylinder 12 injector circuit) and P0312 (cylinder 12 misfire). As always with V-engines, check the manufacturer's cylinder-numbering diagram, since layouts differ between brands.
P0295 symptoms
- Cylinder 12 misfire, largely hidden by the remaining cylinders
- Subtle idle unevenness or exhaust-note change
- Slightly diminished power and smoothness
- Check-engine light; flashing indicates the misfire is active
- Intermittent faults may store the code with no drivability complaints
What it costs to fix P0295
Typical range: $60–$450 · about ~0.5–2 hrs of labor
| If the cause is… | Part | Labor |
|---|---|---|
| Fuel injector (single) | $50–$300 | ~0.5–2 hrs |
| Wiring/connector repair | $5–$50 | ~0.5–2 hrs |
Access dominates the bill on twelve-cylinder engines — rear-of-bank injectors under intake plumbing push labor to the top of the range or past it, and direct-injection injectors carry premium prices. A reachable connector repair is the inexpensive outcome.
The price swings on which cause it turns out to be — so confirm the cause before paying. Diagnose P0295 for my exact vehicle →
How to fix P0295
Advanced — usually a shop job unless you’re well equipped
- Read the freeze frame for a heat or vibration pattern
Note coolant temperature, RPM, and load when P0295 set. A code that only logs once the engine is fully hot, or over rough roads, points to a terminal or winding that opens under heat or movement — and cylinder 12, frequently at the back of a bank near the firewall, is exactly where heat soak is worst.
- Pin-test the cylinder 12 connector
Unplug injector 12 and check both halves for corrosion, a cracked housing, or a terminal that has backed out of its cavity. A matching test pin should drag firmly in each harness socket; one that slides in loosely can lose contact once the engine bay heats up, which the module reports as a high circuit.
- Compare injector 12's resistance cold and hot
Ohm injector 12 on a cold engine, then again straight after a long drive, checking a neighbouring injector each time. A winding that matches cold but reads OL or climbs far above the neighbour once heat-soaked has an internal break that only opens when hot, and the injector needs replacing.
- Noid-light the circuit and test for stray voltage
A noid light on the harness while cranking shows whether the module can still pulse cylinder 12. If it can't, unplug both ends of the control wire, switch the ignition on, and measure to ground: voltage there means the wire has rubbed into a powered circuit, while none means checking that wire end to end for an open.
- Replace injector 12 and code it if required
With the injector condemned, follow the service manual for fuel-pressure relief and access, which on many V12 and W12 layouts means removing the plenum. Fit new seals; on direct-injection engines, observe the high-voltage precautions and enter the injector's calibration code with a scan tool where the system calls for it.
DIY or shop? Freeze-frame reading, connector inspection, and cold-versus-hot resistance checks need only a scanner and a meter, and they can save a shop hours of chasing an intermittent fault. The repair itself is the hard part: twelve-cylinder engines bury the rear injectors under plenums and covers, direct-injected versions add high-voltage circuits and coding, and a short inside the harness can take a long time to find. Bring your findings to a shop that services these engines and let them take it from there.
Tools for the DIY steps: OBD-II scanner with freeze-frame data · Digital multimeter · Noid light set · Terminal test pins · Service manual for your engine
Not sure which step applies to your car? Get the likely cause for your exact vehicle before buying anything for P0295.
Start a case with P0295 and your car. Redline weighs these causes against what your car shows, and names the check that would settle it before you buy parts.
Can I drive with P0295?
Redline can’t determine from a symptom or code alone whether your car is safe to drive.
P0295: common questions
What does P0295 mean compared with P0294?
Both watch the cylinder 12 injector circuit; the split is fault direction. P0295 records high voltage — open circuit, corrosion resistance, or short to battery voltage. P0294 records low voltage — short to ground or a shorted injector coil. The direction guides where diagnosis starts.
Is my injector definitely bad?
Not until it's measured. High-side circuit codes very frequently trace to the connector or harness, and on a twelve-cylinder engine a connector cleaning is dramatically cheaper than injector access. Resistance-test the injector first; replace only if it reads open or clearly out of spec.
The code sets only on hot days. Why?
Heat expands metal and softens insulation, so a marginal connector pin or chafed wire can fault only under certain temperatures — classic intermittent-circuit behavior. That pattern points to the wiring side, and wiggle-testing the warm harness while monitoring the circuit often locates it.
Can I drive with P0295 in the meantime?
Not something a code can answer by itself. The threat of waiting is slow catalyst damage from unburned fuel — and replacing a V12's exhaust hardware costs far more than this repair, so get it fixed promptly. If the check-engine light flashes, stop driving and have it seen.
Related trouble codes
Don’t have a scanner yet? A ~$25 Bluetooth adapter reads codes like P0295 from your phone. See our guide to the best OBD2 Bluetooth adapters. Run a repair shop? See Redline for shops.
Generic OBD-II reference. Manufacturer-specific behavior varies. Confirm with a scan tool and, for safety-related codes, a professional inspection. Cost ranges are reference ranges, not quotes.
Seeing P0295 on your car?
Every problem becomes a Case. Tell Redline what the car is doing: it shows what the evidence supports, what’s still missing, and what to check next, before you approve a repair.
“Inner pad ~1 mm. Outer pad 3 mm.”
Next: check the slide pins move freely before buying parts.