P0271 on 2009-2014 Chevrolet Traverse: Cylinder 4 Injector Circuit High

What's Unique About the 2009-2014 Chevrolet TRAVERSE

On the first-generation Chevrolet Traverse and its platform mates (GMC Acadia, Buick Enclave, Saturn Outlook) with the 3.6L V6 engine, this code is frequently linked to a known issue with the fuel injector wiring harness. A General Motors TSB (#PIP4924D) specifically mentions that the harness can rub through its insulation against the intake plenum, valve cover bolts, fuel lines, or the side of the cylinder head. 🎬 See how wire chafing causes misfires on these V6 engines. This chafing causes a short to voltage, triggering the P0271 code. While a failed injector is always possible, the wiring harness should be considered a primary suspect during diagnosis for this particular vehicle platform.

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 (may be flashing in severe cases)
• Rough or unstable idle
• Engine hesitation or stumbling during acceleration.
• Noticeable loss of engine power
• Reduced fuel economy
• The engine may misfire, which can sometimes be felt as a shudder or vibration.
• Increased emissions

Most Likely Causes

1. Damaged Fuel Injector Wiring Harness 🔴 High Probability → Shop Engine Wiring Harness As documented in GM TSB #PIP4924D, the fuel injector wiring harness is known to rub against multiple points. Common chafe spots include the intake plenum, valve cover bolts, fuel lines, and the side of the cylinder head under the plenum. The constant engine vibration wears through the wire's insulation, causing a short to voltage.
   How to confirm: Visually inspect the entire wiring harness leading to the fuel injectors, especially where it routes around the back of the intake manifold and near the cylinder heads. Look for worn plastic loom, shiny spots on brackets, and exposed copper wire. Wiggle the harness with the engine running to see if it triggers the misfire or a change in engine idle.
   Typical fix: Repair the damaged section of the wire using a weatherproof butt connector and heat shrink tubing. Replace the injector connector pigtail if the damage is at the connector itself. Protect the repaired harness with new plastic loom or anti-abrasion tape and reroute it to prevent future rubbing, securing it with zip ties.
   Est. part cost: $15-$40
2. Faulty Cylinder 4 Fuel Injector 🟡 Medium Probability → Shop Fuel Injector Direct injection fuel injectors operate under high pressure and can fail internally. An electrical short within the injector's coil can cause a 'circuit high' condition.
   How to confirm: Swap the cylinder 4 fuel injector with an injector from another cylinder (e.g., cylinder 2). Clear the codes and drive the vehicle. If the code changes to P0265 (Cylinder 2 Injector Circuit High), the injector is faulty. You can also test the injector's resistance with a multimeter. For the LLT engine (2009-2012), expect ~10-16 Ohms. For the LFX engine (2013-2014), expect 1.2-1.8 Ohms. A reading far outside the specific range for your engine indicates a bad injector.
   Typical fix: Replace the faulty fuel injector. It is often recommended to replace the Teflon seal and O-ring at the same time. Many mechanics suggest replacing all injectors on the same bank, or all six, if they are high mileage, as mixing old and new injectors can cause performance imbalances.
   Est. part cost: $80-$160
3. Corroded or Loose Injector Connector ⚪ Low Probability The connector is exposed to heat and vibration, which can cause it to become brittle or loose over time. Moisture intrusion can also lead to corrosion on the pins.
   How to confirm: Unplug the connector at the cylinder 4 fuel injector and inspect the pins on both the injector and the connector side for green or white corrosion, moisture, or physical damage. Ensure the connector clicks securely into place and the locking tab is not broken.
   Typical fix: Clean the connector pins with electrical contact cleaner and a small brush. Apply a small amount of dielectric grease to the seal before reconnecting. If the connector housing or terminals are damaged, replace the pigtail.
   Est. part cost: $15-$40

Rare But Worth Checking

• Faulty Powertrain Control Module (PCM): → Shop Engine Control Module (ECM) This is the least likely cause. The internal driver circuit for the injector can fail, but all other possibilities, especially wiring and the injector itself, should be exhaustively ruled out before considering PCM replacement.
• Poor Connection at Underhood Fuse Block: In some cases, misfires on an entire bank of cylinders (2-4-6) have been traced to a poor terminal connection underneath the main underhood fuse block. Vibration can cause the connection to become loose or corroded, leading to intermittent power loss for the injector and ignition coil circuits.

Diagnosis Steps

1. Read the codes with an OBD-II scanner and confirm P0271 is present. Note any other codes, like P0304, P0204, or P0270.
2. Identify Cylinder 4. On the transversely mounted 3.6L V6 in the Traverse, the cylinders against the firewall are 1-3-5 (passenger to driver side) and the front bank cylinders near the radiator are 2-4-6. Cylinder 4 is the middle cylinder on the front bank (Bank 2).
3. Perform a detailed visual inspection of the fuel injector wiring harness. Focus on the areas mentioned in TSB #PIP4924D: where the harness runs near the intake plenum, around valve cover bolts, and against fuel lines and the cylinder head. Look for any signs of chafing, melting, or corrosion.
4. Disconnect the electrical connector at the cylinder 4 fuel injector. Check for damage, bent pins, or corrosion. Ensure the lock is secure.
5. To rule out the injector, swap the cylinder 4 injector with one from another cylinder (e.g., cylinder 2). Clear the codes, run the engine, and see if the fault code moves to the new cylinder (e.g., P0265 for cylinder 2). If it does, the injector is bad.
6. If the code remains on cylinder 4 after the swap, the problem is in the wiring or the PCM. Disconnect the harness from the injector and the PCM. Use a multimeter to check for continuity on the two wires running to the cylinder 4 injector connector. Check for a short to voltage on the control wire (this is the most likely cause for a 'Circuit High' code).
7. With the injector unplugged, check the resistance across the two pins on the injector itself. For a 2009-2012 LLT engine, it should be ~10-16 ohms. For a 2013-2014 LFX engine, it should be 1.2-1.8 ohms. An open circuit (OL) or a reading far outside this range confirms a failed injector.
8. If wiring and the injector are confirmed to be good, the final step is to suspect a faulty driver circuit within the Powertrain Control Module (PCM). This is rare and should be the last resort.

Parts You'll Likely Need

• Fuel Injector (OEM #12638530) — This is a common failure part that directly causes the P0271 code when its internal coil shorts. This part number applies to the 2009-2011 LLT engine and has been superseded by part number 12669384.
  Trusted brands: ACDelco, Bosch, Standard Motor Products
  OEM price range: $120-$160
  Aftermarket price range: $80-$120
• Fuel Injector Connector Pigtail — Needed to repair the wiring harness if it is found to be chafed, melted, or corroded at the connector. This allows for a clean splice into the existing harness.
  Trusted brands: Dorman (e.g., 85139), ACDelco
  OEM price range: $25-$40
  Aftermarket price range: $15-$25

Related Codes That Often Appear With This One

• P0304 — P0304 means 'Cylinder 4 Misfire Detected'. Since the P0271 code indicates a problem with fueling cylinder 4, a misfire on that same cylinder is a very common and direct consequence.
• P0204 — P0204 means 'Injector Circuit/Open - Cylinder 4'. This code can appear alongside P0271 if the wiring issue is intermittent, causing both open and high circuit conditions at different times.
• P0270 — P0270 is 'Cylinder 4 Injector Circuit Low'. If the chafed wire intermittently shorts to ground instead of voltage, this code may appear along with P0271.
• P2155 — P2155 is 'Fuel Injector Group 'D' Supply Voltage Circuit'. This code affects cylinders 2, 4, and 6. If the wiring harness damage affects a shared power or ground circuit for the front bank of injectors, you may see this group code along with the individual P0271 code.

Technical Service Bulletins (TSBs) & Recalls

• PIP4924D: Mentions that codes like P0271 can be caused by the fuel injector wiring harness rubbing through and advises inspection at several common contact points. This TSB applies to a wide range of GM vehicles using the 3.0L and 3.6L V6 engines from 2009-2014.

Platform-Specific Known Issues

• A known issue, documented in TSB #PIP4924D, involves the fuel injector wiring harness rubbing through against engine components. Specific chafe points to check are against the intake plenum, at valve cover bolts, against the fuel line, and on the side of the head under the plenum.

Mechanic-Grade Diagnostic Values

• Fuel Injector Resistance (2009-2012 3.6L LLT Engine) — expected: 10 - 16 Ohms. Failure: A reading of zero (short), infinity (open), or significantly outside this range.
• Fuel Injector Resistance (2013-2014 3.6L LFX Engine) — expected: 1.2 - 1.8 Ohms. Failure: A reading outside this very narrow range indicates an internal injector fault.
• Injector Control Circuit Voltage (Boost Phase) — expected: Approx. 65 Volts (pulsed). Failure: A 'Circuit High' code can be triggered by a short to voltage in this high-voltage control circuit.
• Injector Control Circuit Voltage (Hold Phase) — expected: Approx. 12 Volts. Failure: Incorrect voltage during the hold phase can indicate a wiring or PCM driver issue.
• Injector Pulse Width (at normal idle) — expected: 2 - 4 milliseconds (ms). Failure: A value of 0 ms on cylinder 4 while other cylinders show a pulse indicates the PCM is not commanding the injector.

Scan Tool Commands That Help

• GDS2 (GM Factory Scan Tool): Fuel Injector Balance Test — Use this bidirectional test when an injector passes a resistance test but is still suspected of a flow issue. The tool commands each injector to fire and measures the corresponding drop in fuel rail pressure. If the pressure drop for cylinder 4 is significantly different from the others, the injector is mechanically faulty or clogged.

Wiring & Ground Locations

• G110 — Right rear of the engine, mounted to the back of the cylinder head, possibly on a bracket above the power steering pump pressure hose.. This is a primary ground for the Engine Control Module (ECM) and Transmission Control Module (TCM). A poor connection here can cause erratic behavior and incorrect voltage readings from the ECM, potentially triggering a false 'Circuit High' code.
• G101 — Left front of the engine, on the lower block.. This is another critical ground point for the ECM and TCM. Similar to G110, a compromised connection here can lead to various electrical faults, including injector circuit codes.
• Underhood Fuse Block Connection — Under the main fuse block in the engine compartment.. The terminals that supply power to the injector and coil circuits for Bank 2 (cylinders 2, 4, 6) pass through this block. A loose or corroded pin connection underneath the block can cause intermittent power loss to the entire bank, leading to misfires and circuit codes.

Real Owner Repair Stories

• YouTube channel 'Silverback Automotive' (2011 Chevrolet Traverse 3.6L) — Persistent misfire codes for cylinders 2, 4, and 6. Car ran better after a GDI cleaning service, but codes would return intermittently.
  ❌ Tried (didn't work) GDI valve cleaning, Throttle body cleaning, Mass air flow sensor cleaning
  ✅ What actually fixed it The problem was a bad electrical connection for the Bank 2 circuits located underneath the underhood fuse block. The technician removed the fuse block, identified the loose/corroded terminals, tightened them, and reassembled. This permanently resolved the misfire codes for cylinders 2, 4, and 6.
• YouTube channel 'Beer Wrench Garage' (Vehicle not specified, but experiencing P0271 & P2146) — Check engine light with codes P0271 (Cylinder 4 Injector Circuit High) and P2146 (Injector Group 'A' Supply Voltage Circuit).
  ❌ Tried (didn't work) Initial diagnosis pointed towards injectors or ECM.
  ✅ What actually fixed it The owner discovered they had accidentally damaged the fuel injector wiring harness during a previous repair. The fix involved carefully cutting out the damaged sections of wire near the injector connector and splicing in new wire from a donor harness, ensuring proper color matching and using weatherproof connections.

OEM Part Supersession History

• 12638530 → 12669384 — Standard part update or revision by the manufacturer.
  Heads up: This part is for the high-impedance LLT engine and is not compatible with the low-impedance LFX engine (2013-2014). It is recommended to replace injectors as a complete set rather than mixing original and superseded parts.

Model Year Variations Within This Range

• 2009-2012: These models use the 3.6L LLT V6 engine, which has high-impedance fuel injectors (~12 Ohms), a Bosch ECM, and aluminum intake manifolds.
• 2013-2014: These models use the updated 3.6L LFX V6 engine. It features low-impedance fuel injectors (~1.5 Ohms), a Delphi ECM, a composite intake manifold, and cylinder heads with integrated exhaust manifolds. Diagnostic values and some parts are not interchangeable with the earlier LLT engine.