P0265 on 2012-2014 Chevrolet Impala: Cylinder 2 Injector Circuit High Causes and Fixes

What's Unique About the 2012-2014 Chevrolet IMPALA

The 2012-2014 Impala, primarily using the 3.6L LFX V6 direct-injection engine, is highly susceptible to this code due to a known issue with wiring harness integrity. General Motors issued Technical Service Bulletin #PIP4924D, which specifically calls out that the fuel injector wiring harness can rub through against engine components like the intake plenum, valve cover bolts, fuel lines, or the side of the cylinder head. This chafing causes a short circuit that triggers P0265 and related codes. This makes a thorough wiring inspection more critical on this platform than on many other vehicles, where the injector itself might be the immediate primary suspect.

Diagnostic Flowchart

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

Generation note: The 2012-2014 period covers two versions of the Impala. The ninth-generation (until 2013, and as the 'Impala Limited' through 2016) and the new tenth-generation (starting in 2014). Both primarily used the 3.6L LFX V6 engine, to which this guide and the cited TSB apply. The tenth-generation also offered a 2.5L I4, which can experience similar injector circuit faults, though the LFX V6 is the most common subject of TSB #PIP4924D.

Symptoms You May Notice

• Check Engine Light is on or flashing.
• Rough or uneven idle.
• Engine hesitation or stumbling during acceleration.
• Noticeable loss of engine power.
• Increased fuel consumption.
• Strong fuel smell from the engine bay or exhaust.
• Engine stalling.

Most Likely Causes

1. Fuel Injector Wiring Harness Chafing or Damage 🔴 High Probability → Shop Engine Wiring Harness GM TSB #PIP4924D specifically identifies this issue across many models with the LFX engine. The harness routing can cause it to rub against the intake plenum, valve cover bolts, fuel lines, or the cylinder head, leading to a short to voltage.
   How to confirm: Visually inspect the entire length of the fuel injector wiring harness, especially around cylinder 2 (front cylinder on the driver's side bank). Look for worn-through plastic loom and bare or damaged copper wires. Pay close attention to contact points mentioned in the TSB. A 'wiggle test' on the harness with the engine running may cause the idle to change, confirming a wiring fault. 🎬 Watch: How to diagnose and fix the P0265 circuit high code.
   Typical fix: Repair the damaged section of wire using solder and heat-shrink tubing. Protect the repaired area with abrasion-resistant tape or loom and re-route it away from the contact point, possibly using a zip tie to secure it. If damage is at the connector, replace it with a pigtail connector kit.
   Est. part cost: $5-$30
2. Faulty Cylinder 2 Fuel Injector 🟡 Medium Probability → Shop Fuel Injector Direct injectors operate under high stress and pressure. The internal solenoid coil can fail or develop a short, creating a high circuit condition.
   How to confirm: Swap the cylinder 2 fuel injector with one from another cylinder (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 faulty. A professional can also use a scan tool to perform an injector balance test, monitoring fuel pressure drop for each cylinder.
   Typical fix: Replace the faulty fuel injector. On the 3.6L LFX, this is a labor-intensive job that requires removing the upper intake manifold. 🎬 See this walkthrough for intake removal and injector replacement. Many technicians recommend replacing all injectors on that bank (Bank 2) at the same time. The Teflon seals and O-rings are single-use and must be replaced.
   Est. part cost: $70-$180
3. Faulty Powertrain Control Module (PCM) ⚪ Low Probability → Shop Engine Control Module (ECM)
   How to confirm: This should be the last resort after confirming the injector and wiring are good. A professional can use an oscilloscope to test the driver circuit signal from the PCM. A constant high voltage signal, instead of a pulsing square wave, points to a failed PCM driver.
   Typical fix: Replace and reprogram the PCM. This typically requires a professional with specialized tools.
   Est. part cost: $300-$800

Rare But Worth Checking

• Contaminated Fuel: The TSB provided in the prompt (#PIP4924D) mentions inspecting the fuel. While less common for a single-cylinder code, poor quality or contaminated fuel (e.g., with water or high ethanol content) can cause injector internals to corrode or stick, leading to electrical faults. If multiple injector codes are present (e.g., P0262, P0268), this becomes a more likely cause.
• Bent or Damaged Connector Pins: Always inspect the pins on both the injector and the harness connector. A pin can get bent, pushed back, or corroded, causing a poor connection that can lead to high resistance or an intermittent high voltage condition.

Diagnosis Steps

1. Scan for all OBD-II codes. Note if P0265 is accompanied by other codes like P0302 (Cylinder 2 Misfire).
2. Perform a thorough visual inspection of the fuel injector wiring harness for cylinder 2. Per TSB #PIP4924D, pay close attention to areas where it might rub against the intake plenum, valve cover bolts, or fuel lines.
3. If no wiring damage is found, disconnect the injector connector. Check for corrosion or damaged/bent pins on both the injector and the connector.
4. Use a noid light to test for a signal at the injector connector. With the engine running, the noid light should flash. For a 'circuit high' code, you may see the light stay on constantly, indicating a short to voltage.
5. To confirm if the injector is at fault, swap the cylinder 2 fuel injector with another one (e.g., from cylinder 4). Clear the codes, run the engine, and see if the fault code 'moves' to the new cylinder (e.g., P0271). If it does, the injector is the problem.
6. If the code remains P0265 after the swap, the issue is in the wiring or the PCM.
7. Use a multimeter to check for a short to voltage on the control wire for the cylinder 2 injector. Disconnect the PCM and injector. Check for continuity between the injector control wire and a known power source wire in the harness. There should be no continuity.
8. If wiring and the injector are confirmed good, the final possibility is a faulty PCM injector driver, which should be verified by a professional using an oscilloscope.

Parts You'll Likely Need

• Fuel Injector (OEM #12669384) — This is the most likely component to fail after ruling out wiring damage. An internal short in the injector's coil will cause a 'Circuit High' fault. This part number is cited for the 3.6L LFX engine. Always verify with VIN. 🎬 Watch a mechanic install new fuel injectors on this engine.
  Trusted brands: ACDelco, Bosch, Standard Motor Products
  OEM price range: $120-$180
  Aftermarket price range: $70-$110
• Fuel Injector Wiring Harness Repair Kit/Pigtail (OEM #ACDelco PT2183 / GM 88988963) — If the connector or wiring right at the injector is damaged from chafing or heat, a pigtail is used to replace the faulty section without replacing the entire harness. This part number fits many GM vehicles.
  Trusted brands: ACDelco, Dorman
  OEM price range: $30-$50
  Aftermarket price range: $15-$30
• Upper Intake Manifold Gasket Set (OEM #12735534) — To access the fuel injectors on the 3.6L V6, the upper intake manifold must be removed. These gaskets are single-use and must be replaced to prevent vacuum leaks upon reassembly.
  Trusted brands: ACDelco, Fel-Pro
  OEM price range: $25-$40
  Aftermarket price range: $15-$30

Related Codes That Often Appear With This One

• P0302 — P0302 means 'Cylinder 2 Misfire'. Since P0265 indicates a problem with fuel delivery to cylinder 2, a misfire is a direct and expected consequence. The PCM may even shut down the injector to protect the catalytic converter, guaranteeing a P0302 code.
• P0202 — P0202 is a more general 'Injector Circuit/Open - Cylinder 2' code. It can appear with P0265 as the ECM attempts to diagnose the specific electrical fault in the same circuit.
• P0264 — This is the 'Cylinder 2 Injector Circuit Low' code. While less common to see with P0265, it can appear intermittently if a damaged wire is alternately shorting to ground and then to voltage, or if there are multiple wiring issues.

Technical Service Bulletins (TSBs) & Recalls

• PIP4924D: Addresses a Check Engine Light and misfire with various injector codes, including P0265. Recommends inspecting the fuel injector wiring harness for chafing and damage at several common rub points. This TSB covers a wide range of GM vehicles with 3.0L and 3.6L engines, including the 2012-2014 Impala.
• PIP5386A: While for a newer engine, it corroborates the pattern of wiring harness chafing causing injector circuit codes like P0265 on GM V6 platforms.

Platform-Specific Known Issues

• TSB #PIP4924D: This bulletin is highly relevant, stating that for a P0265 code, technicians should carefully inspect the fuel injector wiring harness for chafing against the intake plenum, valve cover bolts, fuel lines, or cylinder head before replacing any components.

Mechanic-Grade Diagnostic Values

• Fuel Injector Coil Resistance (3.6L LFX) — expected: 1.2 - 2.5 Ohms. Failure: A reading near 0 Ohms indicates a short; a reading of OL (infinity) indicates an open circuit.
• Injector Harness Supply Voltage (Key On, Engine Off) — expected: 11.5 - 12.5 Volts. Failure: Voltage significantly below 11.5V points to an upstream wiring or fuse block issue.
• Injector Pulse Width (at idle) — expected: ~2.0 - 3.5 milliseconds. Failure: A wildly different pulse width on one cylinder can indicate a problem, though this is usually a symptom, not a direct cause of a circuit high code.
• Injector Circuit Voltage Waveform (Oscilloscope) — expected: A square wave showing battery voltage (~12V), dropping to near 0V when the ECM grounds the circuit, followed by a large inductive kick/spike (can exceed 50V) upon release.. Failure: A flat line at battery voltage with no drop or spike indicates the ECM is not grounding the circuit or there's an open. A line stuck at a high voltage could indicate a short to power.
• Fuel Pressure (for balance test setup) — expected: 345-414 kPa (50-60 psi). Failure: Pressure outside this range indicates a fuel pump or regulator issue that should be fixed before testing injectors.

Scan Tool Commands That Help

• GDS2 (GM) or high-end bidirectional scanner: Fuel Injector Balance Test — Use this after confirming the wiring is intact. The tool individually fires each injector and measures the fuel pressure drop. If the pressure drop for cylinder 2 is significantly different from the others, it confirms a faulty (likely clogged or sticking) injector without needing to physically swap it.
• GDS2 (GM) or high-end bidirectional scanner: Cylinder Power Balance — This test disables one cylinder at a time and measures the RPM drop. While primarily for misfire diagnosis (P0302), if disabling cylinder 2 causes no change in RPM, it confirms that cylinder was not contributing, which is expected with a P0265 fault.

Wiring & Ground Locations

• Cylinder 2 Injector — The front-most cylinder on the driver's side of the engine (Bank 2).. This is the specific injector and wiring harness section that must be inspected first, as per TSB #PIP4924D.
• Main Engine Ground Strap — Part of the main negative battery cable harness, connecting to the left front of the engine block.. A poor engine ground can cause erratic behavior in multiple sensors and actuators, including the ECM's injector drivers. Verifying this connection is clean and tight is a crucial step in diagnosing any electrical fault.
• ECM Connectors (X1, X2, X3) — Located on the Engine Control Module (ECM). For the LFX, these are typically color-coded: X1 (blue), X2 (black), and X3 (gray).. Advanced diagnosis requires testing the injector control wire for continuity and shorts directly from the ECM connector pin to the injector connector pin, bypassing the entire harness.
• G103 Cowl Ground — Located on the cowl at the left rear of the engine compartment, often near the brake booster.. This ground serves the BCM, Instrument Panel Cluster (IPC), and the Data Link Connector (DLC). While not a direct cause, a fault here can cause communication issues that complicate diagnosis.

Real Owner Repair Stories

• GM Technical Service Bulletin #PIP4924D (Multiple GM vehicles with 3.6L LFX V6, including 2012-2014 Chevrolet Impala) — Check Engine Light on, engine misfire, and various fuel injector circuit codes including P0265.
  ❌ Tried (didn't work) Replacing the fuel injector without inspection., Replacing the ECM without inspection.
  ✅ What actually fixed it Finding and repairing a section of the fuel injector wiring harness that had chafed through against the intake plenum, a valve cover bolt, a fuel line, or the side of the cylinder head. The fix involves repairing the broken wire(s) and protecting the harness with conduit or re-routing it to prevent future contact.

OEM Part Supersession History

• 12611545, 12632255, 12638530 → 12669384 — Standard part evolution for improved reliability or manufacturing process changes.
  Heads up: The newer part number 12669384 is the correct service replacement for the earlier numbers on the LFX engine.

Model Year Variations Within This Range

• 2014: The 2014 model year includes both the older 9th generation ('Impala Limited') and the new 10th generation chassis. While the 3.6L LFX engine is the same, the main engine wiring harness and its routing may differ. There are owner reports of the specific harness for the 10th generation model being discontinued by GM, potentially making a wiring repair (rather than replacement) the only option.