P2149 on 2009-2014 Chevrolet Traverse: Fuel Injector Group B Circuit Causes and Fixes

What's Unique About the 2009-2014 Chevrolet TRAVERSE

The first-generation Traverse, along with its GM Lambda platform siblings (GMC Acadia, Buick Enclave, Saturn Outlook), is known for a specific wiring harness vulnerability. A General Motors Technical Service Bulletin (TSB #PIP4924D) directly addresses code P2149 and points technicians to inspect the fuel injector wiring harness for damage caused by rubbing against engine components, especially the cylinder heads. This makes a wiring fault a much higher probability on this specific vehicle than on others where the code might more commonly indicate a failed injector.

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 vibrates heavily
• Noticeable loss of engine power
• Engine may hesitate or stumble during acceleration
• Difficulty starting the engine
• Increased fuel consumption
• Engine may stall, especially at idle
• Strong smell of unburnt fuel from the exhaust

Most Likely Causes

1. Chafed or Damaged Fuel Injector Wiring Harness 🔴 High Probability → Shop Engine Wiring Harness As documented in GM TSB #PIP4924D, the fuel injector harness is routed in a way that it frequently rubs against the engine block or cylinder head, causing wires to short out or break. This is the most common cause for this specific vehicle, confirmed by numerous owner experiences.
   How to confirm: Carefully perform a visual and physical inspection of the entire fuel injector wiring harness, especially the section that runs over the front valve cover to the Bank 2 (front) injectors. Look for bare wires, melted plastic conduit, or other signs of rubbing. The damage is often found where the harness makes a bend near the cylinder head.
   Typical fix: Repair the damaged section of the wiring harness. This involves cutting out the damaged wires, soldering in new wire, and protecting the repair with heat-shrink tubing. The harness should then be re-secured with zip ties to create clearance and prevent future rubbing. In severe cases, replacing the harness pigtail is necessary.
   Est. part cost: $10-$50
2. Failed Fuel Injector(s) 🟡 Medium Probability → Shop Fuel Injector Direct injection (DI) injectors operate under high pressure and can fail electrically (open coil) or mechanically (stuck open/closed). While less common than the wiring issue for this code, it's still a possibility.
   How to confirm: After confirming the wiring is intact, use a multimeter to check the resistance of each injector in Group B (cylinders 2, 4, 6). Disconnect the main harness plug for that bank and measure between the pins for each injector. A healthy injector for the LLT engine should have a resistance of approximately 1.5-1.6 ohms. An open circuit (infinite resistance) or a reading far out of spec indicates a failed injector.
   Typical fix: Replace the failed fuel injector. It is often recommended to replace all injectors on the affected bank at the same time, especially on higher mileage vehicles. This is a labor-intensive job as it requires removing the intake manifold. 🎬 Watch: This step-by-step guide shows you how to replace the injectors.
   Est. part cost: $50-$150 per injector
3. Loose or Corroded Electrical Connector ⚪ Low Probability
   How to confirm: Disconnect and inspect the main harness connector for the fuel injectors (Bank 2) as well as the individual connectors at each injector. Look for bent pins, corrosion, moisture, or a loose fit. The main bank connector is the most likely point of failure after the harness itself.
   Typical fix: Clean any corrosion from the connector pins using an electrical contact cleaner and ensure a secure connection with dielectric grease. If the connector or its terminals are damaged, the connector pigtail may need to be replaced. 🎬 See how to properly wire in a new fuel injector connector.
   Est. part cost: $15-$50

Rare But Worth Checking

• Faulty Engine Control Module (ECM): → Shop Engine Control Module (ECM) This should be considered only after all other possibilities (wiring, injectors, connectors) have been thoroughly ruled out. An ECM failure is rare but can cause this code if the internal driver circuit for injector Group B fails. A professional diagnosis is recommended before replacing the ECM, as it is expensive and requires programming to the vehicle's VIN.

Diagnosis Steps

1. Scan the ECM for all stored trouble codes. Note P2149 and any other misfire or injector circuit codes (e.g., P0300, P0302, P0304, P0306).
2. Confirm Group B is Bank 2 (the front bank, cylinders 2, 4, 6).
3. Perform a thorough visual inspection of the fuel injector wiring harness as recommended by TSB #PIP4924D. Focus on the section running over the front of the engine to the Bank 2 injectors. Peel back the plastic loom and look for signs of rubbing, melting, or physical damage, especially where the harness contacts the engine block or cylinder heads.
4. If the harness appears damaged, repair the affected wires. Clear the codes and test drive to see if the code returns. Secure the repaired harness away from the contact point using zip ties.
5. If the harness appears intact, disconnect the main connector for the Bank 2 injectors. Use a multimeter to check the resistance of each fuel injector. A normal reading is around 1.5-1.6 ohms. An open circuit (OL) indicates a bad injector.
6. If injector resistance is good, check for 12V supply at the main connector with the key on.
7. Check the continuity of the control wire for each injector from the injector connector back to the ECM connector to rule out a break in a different location.
8. If all wiring and injectors are confirmed to be good, the fault may lie with the ECM's injector driver circuit, which may require professional diagnosis.

Parts You'll Likely Need

• Fuel Injector Wiring Harness Repair Kit/Pigtail (OEM #PT2712, PT2618) — This is needed to fix chafed or melted wires, which is the most common cause of P2149 on this vehicle per the TSB. Specific pigtail part numbers can vary.
  Trusted brands: ACDelco, Dorman, Standard Motor Products
  OEM price range: $40-$80
  Aftermarket price range: $15-$50
• Fuel Injector (OEM #12638530) — If the wiring is intact, one or more injectors in Group B may have failed electrically. This is the correct part number for the 3.6L LLT engine.
  Trusted brands: ACDelco, Bosch, Standard Motor Products
  OEM price range: $100-$160
  Aftermarket price range: $50-$90

Related Codes That Often Appear With This One

• P2146 — This code is for 'Fuel Injector Group 'A' Supply Voltage Circuit/Open'. Seeing both P2146 and P2149 together strongly points to a significant wiring issue affecting both injector banks or a problem with the ECM.
• P0300 — This is a 'Random/Multiple Cylinder Misfire Detected' code. Since P2149 disables an entire bank of injectors (cylinders 2, 4, and 6), it will cause multiple cylinders to misfire, triggering P0300.
• P0302, P0304, P0306 — These are misfire codes for specific cylinders (2, 4, and 6). On the Traverse 3.6L engine, these cylinders make up the front bank (Bank 2), which is designated as Group B. Seeing these codes alongside P2149 confirms which bank is affected.
• P0201-P0206 — These codes indicate specific injector circuit malfunctions (e.g., P0202 for cylinder 2). They can appear alongside P2149, helping to pinpoint the issue. The TSB #PIP4924D lists these codes as related.

Technical Service Bulletins (TSBs) & Recalls

• PIP4924D: Instructs technicians to inspect the fuel injector wiring harness for rub through or internal wire opens when encountering a list of codes including P2149, P2146, and P0201-P0206.

Platform-Specific Known Issues

• TSB #PIP4924D explicitly calls out that the fuel injector wiring harness is prone to rubbing through or developing internal opens, leading to P2149 and other related injector codes.
• Owner forums for the Traverse and its platform mates are filled with accounts of this exact failure, with most confirming the fix was repairing the harness where it chafed against the engine.

Mechanic-Grade Diagnostic Values

• Fuel Injector Coil Resistance — expected: 1.5 - 1.6 ohms. Failure: A reading of 0 ohms (short), infinite/OL (open), or a value significantly different from the other injectors.
• Injector Supply Voltage — expected: 11.5 - 12.5 Volts. Failure: Voltage below 9V indicates a circuit problem.
• Wiring Harness Continuity — expected: < 0.2 ohms. Failure: Resistance greater than 0.2 ohms from the ECM output pin to the injector connector indicates a high-resistance path in the wire.

Scan Tool Commands That Help

• GDS2 (GM Global Diagnostic System 2): Fuel Injector Balance Test — Use this after confirming wiring integrity. The tool commands each injector to fire while monitoring fuel pressure drop, which can identify a mechanically stuck or clogged injector that might otherwise test fine electrically.
• GDS2 (GM Global Diagnostic System 2): Output Control / Bidirectional Control — This allows a technician to command the injector bank circuit on and off directly from the scan tool. It helps verify if the ECM driver circuit is capable of controlling the circuit and if the wiring is intact up to the point of failure.

Wiring & Ground Locations

• Injector Harness Chafe Points — Most commonly found where the harness routes over the front (Bank 2) valve cover, making contact with the intake plenum, valve cover bolts, or fuel lines.. This is the specific failure location identified in TSB #PIP4924D and is the number one cause of P2149 on this platform.
• G103 / G104 — Primary engine grounds bolted to the cylinder heads. G103 is often on the front of the passenger side (Bank 1) cylinder head, and G104 is on the rear of the driver's side (Bank 2) cylinder head.. A loose or corroded ground at these points can cause an unstable reference for the ECM, leading to erratic behavior of the injector driver circuits and potentially triggering false circuit codes.
• ECM Connectors (X1, X2) — Located on the Engine Control Module (ECM) at the front of the engine compartment.. These connectors are the origin point for the injector control circuits. Technicians must test for continuity from the specific pins in these connectors to the injector harness to isolate a wire break.

Real Owner Repair Stories

• acadiaforum.net user report (GMC Acadia 3.6L (Lambda Platform Sibling)) — Check engine light with code P2149 and misfires on cylinders 2, 4, and 6.
  ❌ Tried (didn't work) Initial diagnosis was leaning towards bad fuel injectors.
  ✅ What actually fixed it A thorough inspection of the wiring harness, as suggested by TSB PIP4924D, revealed several wires had chafed through their insulation where the harness rested on the engine. The owner repaired the damaged wires, secured the harness to prevent future rubbing, and the code was resolved.
• YouTube Channel 'Beer Wrench Garage' (Chevrolet Traverse (2009-2014 platform)) — Engine running rough, Check Engine Light with codes P2146 (Group A) and P0271.
  ❌ Tried (didn't work) Considered replacing the fuel injector first.
  ✅ What actually fixed it Discovered a broken wire within the fuel injector wiring harness, exactly as described in TSB PIP4924D. Repairing the wire fixed the issue.

OEM Part Supersession History

• 12638530 → 12669384 — Standard part revision by the manufacturer for improvements or supplier changes.
  Heads up: While the new part number is the correct replacement, it is strongly recommended to replace all injectors on a bank at the same time, especially if using aftermarket parts, to ensure consistent flow rates and performance.

Model Year Variations Within This Range

• 2013-2014: Starting in model year 2013, the Traverse received a mid-cycle refresh and the engine was updated from the 3.6L LLT to the 3.6L LFX. While architecturally similar, there may be minor differences in wiring, connectors, or component locations. However, the primary cause of P2149 related to harness chafing is known to affect both engine versions in this chassis.