P0262 on 2012-2014 Chevrolet Impala: Cylinder 1 Injector Circuit High Causes and Fixes

What's Unique About the 2012-2014 Chevrolet IMPALA

The 2012-2014 Impala uses the 3.6L LFX V6 engine, a direct-injection motor. While the P0262 code is generic, GM has issued Technical Service Bulletins (TSBs) like #PIP4924D for this engine family that group P0262 with over twenty other injector codes. This bulletin specifically instructs technicians to inspect the engine wiring harness for chafing against components like the intake plenum, valve cover bolts, fuel lines, and the side of the cylinder head. This known vulnerability makes a thorough wiring inspection a critical diagnostic step before replacing the injector itself.

Diagnostic Flowchart

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

Generation note: This range covers the end of the ninth generation (2012-2013) and the start of the tenth generation (2014). A ninth-generation 'Impala Limited' was also sold to fleets in 2014-2016. All these models used the 3.6L LFX V6 engine, so the information in this guide is relevant across the entire 2012-2014 range, provided the vehicle has this engine.

Symptoms You May Notice

• Check Engine Light is on
• Engine misfire, often felt as a shake or stumble
• Rough or unstable idle
• Reduced engine power and poor acceleration.
• Worse than normal fuel economy.
• Black smoke from the exhaust.
• Strong smell of unburnt fuel.

Most Likely Causes

1. Faulty Cylinder 1 Fuel Injector 🔴 High Probability → Shop Fuel Injector The fuel injector can develop an internal short circuit or high resistance in its coil, causing the high voltage condition detected by the PCM. This is a very common failure part for this specific code.
   How to confirm: Measure the resistance of the fuel injector with a multimeter; it should be within the manufacturer's specification (typically 1.5-2.3 ohms for the LFX direct injector). A simpler method is to swap the cylinder 1 injector with another cylinder's injector (e.g., cylinder 3). Clear the codes and drive. If the code follows the part and changes to P0268 (Cylinder 3 Injector Circuit High), the injector is faulty.
   Typical fix: Replace the faulty fuel injector. Since the intake manifold must be removed to access the injectors, many owners and shops recommend replacing all three injectors on that bank (or all six) at the same time to save on future labor costs. 🎬 Watch this complete walkthrough for intake removal and injector replacement.
   Est. part cost: $70-$180
2. Wiring Harness Damage 🟡 Medium Probability GM TSB #PIP4924D specifically addresses a range of injector codes, including P0262, on this engine family. The wiring harness is routed tightly and can chafe against the intake plenum, valve cover bolts, fuel lines, or the side of the cylinder head under the plenum, causing a short to voltage.
   How to confirm: Visually inspect the entire wiring harness leading to the cylinder 1 fuel injector. A wiggle test on the harness with the engine running may induce a misfire, helping to pinpoint the location. Look for any signs of rubbing, melting, or exposed wires, particularly where the harness bends or makes contact with other engine parts as described in the TSB.
   Typical fix: Repair the damaged section of wire using solder and heat shrink. Protect the harness from future damage using a protective wire loom, high-temperature tape, or by re-routing it away from the contact point. In severe cases, an injector connector pigtail or a new engine harness may be needed.
   Est. part cost: $15-$500
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 may need to use an oscilloscope to test the driver signal from the PCM. If the signal is stuck 'on' or absent when it should be pulsing, the PCM's internal driver circuit is likely faulty. Because LFX injectors use a 65-volt capacitive charge, a standard noid light or multimeter is not sufficient for testing the control circuit.
   Typical fix: Replace and reprogram the PCM. The new module must be programmed with the vehicle's VIN.
   Est. part cost: $300-$800

Rare But Worth Checking

• Corroded or Loose Injector Connector:

Diagnosis Steps

1. Read the codes with an OBD-II scanner and note any other codes present, especially P0301 or other injector codes.
2. Perform a thorough visual inspection of the wiring harness for the cylinder 1 injector. Per TSB #PIP4924D, pay close attention to areas where it might rub against the intake plenum, valve cover bolts, and fuel lines.
3. Disconnect the injector and measure its internal resistance with a multimeter. Compare the reading to the other injectors; a reading outside of the 1.5-2.3 ohm range or significantly different from others indicates a faulty injector.
4. A good DIY test is to swap the cylinder 1 fuel injector with one from another cylinder (e.g., cylinder 3). Clear the codes and drive the vehicle. If the code changes to P0268 (Cylinder 3 Injector Circuit High), the injector is confirmed to be the problem.
5. If the code does not move with the injector, the issue is likely in the wiring or the PCM.
6. Use of a standard noid light is not recommended for GDI injectors. A lab scope is required to properly test the 65-volt capacitive discharge signal from the PCM.
7. If a lab scope is unavailable, perform a continuity test on the control and power wires between the injector connector and the PCM connector to rule out a break or short in the harness.
8. If all other tests pass, the PCM is the most likely culprit, though this is the least common cause.

Parts You'll Likely Need

• Fuel Injector (OEM #12638530) — This is the most common component to fail internally, causing the 'Circuit High' condition. The original part number 12638530 has been superseded by GM part number 12669384.
  Trusted brands: ACDelco, Bosch, Hitachi, Standard Motor Products
  OEM price range: $120-$180
  Aftermarket price range: $70-$130
• Intake Manifold Gasket Set (OEM #12678526) — The upper intake manifold must be removed to access the fuel injectors on the 3.6L LFX engine. The gaskets are single-use and must be replaced during reassembly to prevent vacuum leaks. 🎬 See how to replace the intake and injectors on GM 3.6L engines.
  Trusted brands: ACDelco, Fel-Pro, Mahle
  OEM price range: $30-$50
  Aftermarket price range: $15-$30
• Fuel Injector Seal Kit — Direct injectors use single-use Teflon seals that must be replaced whenever an injector is removed to prevent fuel and compression leaks. Special tools are often required for proper installation.
  Trusted brands: ACDelco, Fel-Pro
  OEM price range: $10-$20 per injector
  Aftermarket price range: $5-$15 per injector

Related Codes That Often Appear With This One

• P0301 — This code means 'Cylinder 1 Misfire Detected'. It is a direct result of the P0262 fault, as the injector circuit problem prevents proper fueling, causing the cylinder to misfire.
• P0201 — This is a general fault code for the 'Cylinder 1 Injector Circuit/Open'. It can appear alongside P0262, as both point to an electrical fault in that specific circuit and are often listed together in GM service bulletins.
• P0261, P0264, P0267, etc. — If you see other injector circuit codes for different cylinders (e.g., P0261 for circuit low, P0264 for cylinder 2), it strongly points to a widespread wiring harness issue or a failing PCM, as multiple injector circuits are affected.

Platform-Specific Known Issues

• TSB #PIP4924D: This Manufacturer Technical Service Bulletin is critical for this code on this vehicle. It covers a wide range of engine and fuel system diagnostic codes, including P0262. It instructs technicians to inspect the engine wiring harness for potential chafing that could cause shorts. Specific inspection points are against the intake plenum, at valve cover bolts, against the fuel line, and on the side of the cylinder head under the plenum.
• Cylinder Location: On the transverse-mounted 3.6L LFX V6, Cylinder 1 is on the rear bank (closest to the firewall), on the passenger side of the engine. Accessing this injector requires removing the upper intake manifold.

Mechanic-Grade Diagnostic Values

• Fuel Injector Coil Resistance — expected: 1.5 to 2.3 Ohms. Failure: A reading of zero (short), infinity (open), or significantly outside the expected range.
• Fuel Injector Circuit Voltage (Lab Scope) — expected: A capacitive charge of approximately 65 volts, followed by a pulse to ground.. Failure: Absence of the 65V charge or a signal that is stuck high or does not pulse to ground indicates a PCM driver or wiring fault. A standard 12V test light or noid light is insufficient for this test.
• Fuel Injector Current (Lab Scope with Amp Clamp) — expected: A peak amperage of approximately 13 amps when the injector is commanded on.. Failure: No current flow, or current that is significantly lower or higher than expected, points to a fault in the injector or control circuit.

Scan Tool Commands That Help

• GM GDS2 (or equivalent high-level scan tool): Fuel Injector Balance Test — This automated test commands each injector to fire for a set duration and measures the corresponding drop in fuel rail pressure. It is used to identify injectors with poor flow or clogging, which would not typically set a 'Circuit High' code but is a useful health check if injectors are being replaced. A cylinder that shows a significantly different pressure drop than the others indicates a flow problem.
• GM GDS2: Clear Secured High Voltage DTCs — Some critical powertrain codes, especially in hybrid or advanced systems, may be 'secured' and cannot be cleared by a standard OBD-II clear command. This function in the dealer-level software may be required to clear persistent faults after a repair has been made.

Wiring & Ground Locations

• Cylinder 1 Injector Control Wire — Based on similar GM LFX wiring, this is likely a Brown wire at the ECM. A full wiring diagram for the specific vehicle is required for definitive confirmation of the pin number at the ECM connector.. This wire carries the ground signal from the PCM to fire the injector. A short to voltage on this wire will cause a P0262 code. A continuity test from the injector connector to the PCM connector pin is the definitive wiring test.
• G104 (Engine Ground) — Located on the front of the engine block on the 3.6L LFX V6.. A poor engine ground can cause incorrect voltage readings and erratic behavior across multiple sensors and actuators, including the fuel injectors. GM has issued bulletins for other issues that were resolved by cleaning and tightening this specific ground.
• G111 (Engine Ground) — Located on the engine block, above the starter motor.. This is a primary engine ground. A loose or corroded connection here can affect the entire engine management system and potentially cause false circuit codes.
• G102 (Engine Ground) — Located near the battery.. Serves as a critical grounding point for the engine harness. Corrosion or a loose connection can introduce electrical noise and unstable sensor readings.

OEM Part Supersession History

• 12638530 → 12669384 — Standard part evolution for improved reliability or manufacturing process. The new part number also replaces older numbers 12611545 and 12632255.

Model Year Variations Within This Range

• 2014: In 2014, Chevrolet sold two different Impalas. The 'Impala Limited' was a carryover of the 9th generation body style (2012-2013) and uses the same parts. The all-new 10th generation 'Impala' was also introduced. While both offered the 3.6L LFX V6, other body and chassis parts are completely different. When ordering parts for a 2014, it is critical to specify if it is a 'Limited' model to ensure compatibility.