P0265 on 2010-2014 GMC Terrain: Injector Circuit High Causes and Fixes

What's Unique About the 2010-2014 Gmc TERRAIN

For the 2010-2014 GMC Terrain and its platform-mate, the Chevrolet Equinox, a notable Technical Service Bulletin (TSB #PIP4924D) points to a known issue with the fuel injector wiring harness. The bulletin advises technicians to carefully inspect the harness for chafing or rubbing against engine components like the intake plenum, valve cover bolts, or fuel lines, which can cause a short circuit and trigger codes like P0265. This makes a thorough wiring inspection a critical first step on these vehicles, even before testing the injector itself.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• Check Engine Light is on
• Engine runs rough or idles poorly
• Noticeable engine misfire, which may feel like a shudder
• Hesitation or stumbling during acceleration
• Reduced fuel economy
• A smell of raw fuel from the exhaust
• Black smoke from the tailpipe

Most Likely Causes

1. Wiring Harness or Connector Issue 🔴 High Probability GM issued multiple versions of TSB #PIP4924 specifically for these vehicles due to the fuel injector wiring harness chafing against engine parts. Common rub-through spots are against the intake plenum, valve cover bolts, and fuel lines, leading to a short to voltage that triggers P0265. This is a well-documented failure pattern.
   How to confirm: Visually inspect the entire wiring harness leading to the cylinder 2 injector. Pay extremely close attention to areas where the harness makes contact with metal components. Use a multimeter to check for voltage on the control wire at the injector connector with the key on; a steady high voltage (over 5V) with the engine off points to a short to power in the harness.
   Typical fix: Repair the damaged section of the wiring harness by soldering and heat-shrinking the affected wire. Reroute the harness slightly or add protective conduit to prevent future chafing. If the connector is damaged, replace the pigtail.
   Est. part cost: $15-$50
2. Faulty Cylinder 2 Fuel Injector 🟡 Medium Probability → Shop Fuel Injector The direct injection (GDI) fuel injectors on these engines operate under high pressure and can fail internally. An internal short in the injector's coil windings will cause the resistance to drop, leading to a 'high circuit' condition detected by the ECM.
   How to confirm: Test the injector's resistance with a multimeter. For the GDI engines in the Terrain, the resistance should be between 1.1 and 2.0 Ohms. A reading near zero indicates a short. The most definitive test is to swap the cylinder 2 injector with another (e.g., cylinder 4). Clear the codes and run the engine. If the code changes to P0271 (Cylinder 4 Injector Circuit High), the injector is confirmed bad.
   Typical fix: Replace the faulty fuel injector. It is often recommended to replace the Teflon seal and retaining clip when replacing an injector.
   Est. part cost: $70-$180
3. Faulty Engine Control Module (ECM) ⚪ Low Probability → Shop Engine Control Module (ECM)
   How to confirm: This is diagnosed by exclusion. If the injector and wiring have been tested and are confirmed to be good, but the fault persists, the ECM's internal injector driver is the likely cause. A noid light test that shows the light staying on continuously instead of pulsing would point to a faulty ECM driver that is stuck 'on'.
   Typical fix: Replace and reprogram the Engine Control Module. This requires special tools for programming it to the vehicle's VIN.
   Est. part cost: $300-$800

Diagnosis Steps

1. Read the trouble codes with an OBD-II scanner and confirm P0265 is present. Note any other codes, especially P0302 or other injector codes.
2. Identify cylinder #2. On the 2.4L I4 engine, cylinders are numbered 1-2-3-4 from the passenger side (front of engine/belts) to the driver side. On the 3.0L/3.6L V6 engines, cylinder #2 is the front-most cylinder on the passenger side (front bank, Bank 2).
3. Critical Step for this Platform: Thoroughly inspect the fuel injector wiring harness. Per TSB PIP4924D, check for chafing against the intake plenum, valve cover bolts, fuel lines, and the side of the cylinder head. Manipulate the harness while the engine is idling (if possible) to see if it affects the misfire.
4. Disconnect the injector and use a multimeter to measure its internal resistance. It should be between 1.1 and 2.0 Ohms for these GDI engines. Compare it to a known-good injector on another cylinder to verify. A reading near 0 Ohms indicates a shorted injector.
5. Perform a noid light test. Connect a noid light to the injector connector. Start the engine; the light should flash steadily. If the light is off, there's an open in the circuit. If the light is on constantly, the ECM driver may be shorted or there's a short to voltage in the harness.
6. If you suspect the injector, swap it with an adjacent one (e.g., swap injectors from cylinder 2 and 4). Clear the codes and run the engine. If the code changes to P0271 (Cylinder 4 Injector Circuit High), the injector is faulty.
7. If the code remains P0265 after the swap, the problem lies in the wiring or the ECM.
8. If the wiring and injector are confirmed good, the final step is to suspect the ECM.

Parts You'll Likely Need

• Fuel Injector (OEM #12634126 (For 3.0L/3.6L V6), 12633784 (For 2.4L I4)) — This is a common failure point for a P0265 code if wiring is ruled out. An internal short in the injector's coil windings will cause this fault.
  Trusted brands: ACDelco, Hitachi, Standard Motor Products, GB Remanufacturing
  OEM price range: $120-$180
  Aftermarket price range: $70-$110
• Fuel Injector Wire Pigtail — If the wiring is damaged right at the connector, or the connector itself is corroded or broken, replacing the pigtail is the most effective repair.
  Trusted brands: ACDelco, Dorman, Standard Motor Products
  OEM price range: $25-$40
  Aftermarket price range: $15-$25

Related Codes That Often Appear With This One

• P0302 — This code means 'Cylinder 2 Misfire Detected.' Since P0265 indicates a problem with fuel delivery to cylinder 2, a misfire in that same cylinder is a direct and very common consequence.
• P0202 — This code for 'Injector Circuit/Open - Cylinder 2' is a related fault. Depending on the exact nature of the electrical failure (open vs. short), either P0202 or P0265 may be set.
• P0262, P0268, P0271 — If other injector circuit high/low codes are present for other cylinders, it strongly suggests a systemic issue like a damaged wiring harness affecting multiple wires, rather than a single failed injector.

Technical Service Bulletins (TSBs) & Recalls

• Bulletin #PIP4924D: Supersedes previous versions and covers up to 2014 models. Explicitly calls out inspecting the fuel injector wiring harness for chafing against the intake, valve covers, and fuel lines as a primary diagnostic step for a list of injector codes including P0265.

Platform-Specific Known Issues

• A Technical Service Bulletin (TSB #PIP4924D) was issued for 2010-2014 models. It notes that various injector codes, including P0265, can be set along with a misfire. It specifically directs technicians to 'Carefully inspect the fuel injector wiring harness for rub through or internal wire opens.' This makes a wiring fault a higher-than-usual probability on the GMC Terrain and its platform mates.
• The Chevrolet Equinox, built on the same platform with the same engines, experiences the identical P0265 issue, often traced back to the same wiring harness chafing points.

Mechanic-Grade Diagnostic Values

• High-Pressure Fuel System (2.4L Engine) — expected: The system is designed to withstand pressures up to 600 PSI.. Failure: While not a direct test for P0265, pressure fluctuations can indicate systemic fuel delivery issues that may affect injectors.
• Injector Control Circuit Voltage Waveform — expected: When the ECM grounds the circuit to fire the injector, voltage should drop to near 0V. When the ECM de-energizes the injector, voltage should momentarily peak before settling back to system voltage (approx. 12V).. Failure: For P0265, the voltage on the control circuit remains high when it should be pulled to ground, or does not return to normal system voltage.

Scan Tool Commands That Help

• GM Tech 2 / GDS2: Fuel Injector Balance Test — This is a definitive test to confirm if an injector is mechanically faulty or partially clogged, which can sometimes lead to electrical fault codes. The test individually pulses each injector with the engine off and measures the corresponding drop in fuel rail pressure. The pressure drop should be nearly identical across all cylinders. A significantly smaller or larger pressure drop for cylinder 2 points to a faulty injector.

Wiring & Ground Locations

• Cylinder 2 Injector Control Wire — On the 73-pin ECM connector (often designated J2 or X2), the control wire for the cylinder 2 fuel injector is at pin J2-16. The wire color is typically Light Blue (LT BLU).. This is the specific pin to test at the ECM for a short to voltage or an open circuit when diagnosing a persistent P0265 after the injector and harness at the engine have been checked.
• G105 / G112 — These are primary engine block grounds. On the 2.4L, G105 is at the rear of the engine and G112 is at the lower left front. On the 3.0L V6, both are located on the left rear of the engine.. The ECM and its driver circuits rely on a solid engine ground. A loose or corroded ground at these locations can cause floating voltages and erratic behavior in sensor and actuator circuits, including the fuel injectors.
• G103 / G108 — Located on the back of the cylinder heads. These are known on similar GM platforms to cause a wide range of drivability problems when loose or corroded.. A poor ground connection at the cylinder head can affect multiple engine components and create electrical noise that could interfere with injector operation or the ECM's ability to correctly monitor the circuit.

OEM Part Supersession History

• 12642128 → 12634126 — Standard part revision and update by the manufacturer.

Model Year Variations Within This Range

• 2010-2012 vs 2013-2014: The optional V6 engine changed. 2010-2012 models used the 3.0L LF1 V6. For 2013-2014, this was replaced with the 3.6L LFX V6. While both are from the same GM 'High Feature' family, they have different displacements, power outputs, and potentially different intake manifolds and fuel system components. The 2.4L I4 was available for all years in this range.