P2152 on 2009-2014 GMC Acadia: Fuel Injector Group C Circuit Causes and Fixes

What's Unique About the 2009-2014 Gmc ACADIA

The first-generation GMC Acadia and its platform mates (Buick Enclave, Chevrolet Traverse, Saturn Outlook) with the 3.6L direct-injection V6 are known for this specific issue. General Motors issued a Technical Service Bulletin (TSB #PIP4924D) that directly links P2152 and other injector group codes to a wiring harness design that is prone to rubbing through its insulation. The harness routing brings it into close contact with engine components like the intake plenum, valve cover bolts, fuel lines, and the side of the cylinder head, leading to chafing and electrical faults over time.

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)
• Engine runs rough or vibrates (misfires).
• Noticeable loss of power and acceleration.
• Engine may hesitate or stumble, especially under load
• Engine may stall at low speeds or idle.
• Reduced Engine Power message may appear on the driver information center

Most Likely Causes

1. Fuel Injector Wiring Harness Chafed or Broken 🔴 High Probability → Shop Engine Wiring Harness As documented in TSB #PIP4924D, the harness is routed in a way that causes it to rub against engine parts, leading to shorts or open circuits. This is the most common cause by a significant margin.
   How to confirm: Carefully perform a detailed visual and tactile inspection of the entire fuel injector harness, specifically the passenger side bank. Pay close attention to areas where it contacts the intake plenum, valve cover bolts, sharp edges of the cylinder head, and metal fuel lines. Look for worn insulation, shiny copper wires, or complete breaks. The damage is often found on the underside of the harness where it's not immediately visible. A voltage drop test between the ECM and the injector connector should show less than 0.5V; a larger drop indicates high resistance in the wire.
   Typical fix: If damage is found, repair the specific wires using solder and heat-shrink tubing for a durable connection. Protect the repaired area and other vulnerable spots with high-quality electrical tape, split-loom tubing, or an anti-abrasion sleeve. If damage is extensive or in multiple locations, the entire harness section (GM Part #12621096) should be replaced.
   Est. part cost: $5-$20 for repair materials, $100-$160 for a new harness section.
2. Failed Fuel Injector 🟡 Medium Probability → Shop Fuel Injector Direct injection fuel injectors operate under high pressure and can fail electrically over time, though it is less common than the wiring issue for this specific code.
   How to confirm: If the wiring harness is confirmed to be in good condition, test the resistance of the injectors in Group C (cylinders 2 and 5) using a multimeter. It is critical to use the correct specification for your engine year. For the 2009-2011 LLT engine, expect 11-14 ohms. For the 2012-2014 LFX engine, expect 1.2-2.5 ohms. An open circuit (infinite resistance) or a reading far out of spec indicates a failed injector.
   Typical fix: Replace the faulty fuel injector. It is often recommended to replace all injectors on that bank, or all six, if they are high-mileage to ensure balanced performance.
   Est. part cost: $40-$90 per injector.
3. Loose or Corroded Connector ⚪ Low Probability Engine bay heat and vibration can affect connectors over time. Water intrusion from engine washing can also cause corrosion.
   How to confirm: Unplug and inspect the main harness connector (often a large, multi-pin connector near the back of the intake) and the individual fuel injector connectors for any signs of corrosion (green or white powder), moisture, or bent/backed-out pins. Ensure they are fully seated.
   Typical fix: Clean the connector pins with an electrical contact cleaner and a small brush. Apply dielectric grease before reconnecting to prevent future moisture intrusion. If pins are damaged, the connector pigtail may need to be replaced.
   Est. part cost: $10-$30 for a new pigtail connector.

Rare But Worth Checking

• Faulty Engine Control Module (ECM): → Shop Engine Control Module (ECM) This is the least likely cause. The ECM's internal driver circuit for the injector group can fail, but all other possibilities, especially the wiring harness, must be exhaustively ruled out first. A short in the harness can sometimes damage the ECM driver, requiring both to be replaced.

Diagnosis Steps

1. Scan the ECM for all stored trouble codes. Note P2152 and any accompanying misfire (P030x) or other injector group codes (P2149, P2155).
2. Begin with a detailed visual inspection of the fuel injector wiring harness, as this is the most likely cause. This is the passenger side harness on the 3.6L V6. Follow the path of the harness from the main connector to each injector, focusing on the common chafe points identified in TSB #PIP4924D: against the intake plenum, sharp edges of valve cover bolts, and where it might rub against metal fuel lines or the side of the cylinder head. Use a mirror and flashlight to inspect all sides of the harness.
3. If visible damage (bare or broken wires) is found, repair the wiring using solder and heat-shrink tubing. Protect the repaired section with a wire loom or abrasion-resistant tape. Clear the codes and test drive to see if the code returns.
4. If no visible damage is found, disconnect the harness from the ECM and the injectors. Use a multimeter to test for continuity on the power supply wire for Group C from the main ECM connector to the injector connectors for cylinders 2 and 5. Also, check for a short to ground on that same wire.
5. If wiring and connectors are confirmed to be good, test the internal resistance of the fuel injectors in Group C. Disconnect the injector and measure resistance across its two pins. CRITICAL: Use the correct OEM specification for your model year. For 2009-2011 (LLT engine), expect 11-14 ohms. For 2012-2014 (LFX engine), expect 1.2-2.5 ohms. An out-of-spec reading indicates a faulty injector.
6. If both the wiring and the injectors test good, the final and least likely possibility is a fault within the Engine Control Module (ECM) itself. This should be considered the last resort after all other possibilities are exhausted.

Parts You'll Likely Need

• Fuel Injector Wiring Harness (Right/Passenger Side) (OEM #12621096) — This is the most common failure point for code P2152 on this vehicle due to a known chafing issue. This part number is for the passenger side bank harness.
  Trusted brands: ACDelco, GM Genuine
  OEM price range: $100-$160
  Aftermarket price range: $70-$120
• Fuel Injector (OEM #12638530) — If the wiring is intact, an injector in the group may have failed electrically. Part number varies by engine type (LLT vs LFX).
  Trusted brands: ACDelco, Bosch, Delphi
  OEM price range: $70-$110
  Aftermarket price range: $40-$80
• Wire Repair Supplies — For minor harness damage, a simple wire repair is often sufficient and much more cost-effective than replacing the entire harness.
  Trusted brands: 3M
  OEM price range: $10-$25
  Aftermarket price range: $5-$15

Related Codes That Often Appear With This One

• P0300 — Stands for 'Random/Multiple Cylinder Misfire Detected.' Since P2152 disables an entire group of injectors (e.g., cylinders 2 and 5), it will cause multiple cylinders to misfire.
• P0302, P0305 — Specific misfire codes for the cylinders that belong to injector Group C (cylinders 2 and 5).
• P2149, P2155 — These are codes for other injector groups ('B' and 'D'). If the wiring harness damage is severe or affects multiple wires, it can impact the circuits for several injector groups simultaneously, often blowing the ECM fuse.

Technical Service Bulletins (TSBs) & Recalls

• PIP4924D: Addresses SES light and misfires with various injector codes (including P2152) caused by the fuel injector wiring harness rubbing through or having internal wire opens. It applies to a wide range of GM vehicles with 3.0L and 3.6L V6 engines from 2009-2012+.

Platform-Specific Known Issues

• A known issue documented in GM Technical Service Bulletin #PIP4924D points directly to the fuel injector wiring harness chafing against engine components, causing an open or short circuit and triggering codes like P2152. The bulletin specifically calls out contact points against the intake plenum, valve cover bolts, and fuel lines as common problem areas.

Mechanic-Grade Diagnostic Values

• Fuel Injector Resistance (2009-2011 3.6L LLT Engine) — expected: 11 - 14 Ohms. Failure: A reading of 0 ohms (short), infinity/OL (open), or significant deviation from this range.
• Fuel Injector Resistance (2012-2014 3.6L LFX Engine) — expected: 1.2 - 2.5 Ohms. Failure: A reading outside this range indicates an internal injector fault. Note the significant difference from the earlier LLT engine.
• Injector Circuit Voltage Drop — expected: Less than 0.5 Volts. Failure: A voltage difference greater than 0.5V between the ECM connector and the injector connector indicates high resistance in the wiring.
• Injector Pulse Width (at idle) — expected: 2 - 4 milliseconds (ms). Failure: A value of 0 ms on the affected cylinders while others are pulsing indicates the ECM is not commanding the injector.

Scan Tool Commands That Help

• GM GDS2 / Tech2: Fuel Injector Balance Test — This bidirectional test commands each injector to fire individually while monitoring RPM drop or fuel pressure drop. It helps confirm if the cylinders in Group C (2 and 5) are truly not contributing, which is expected with P2152. A lack of RPM change when disabling these cylinders confirms the fault is active.
• GM GDS2 / Tech2: Cylinder Power Balance / Injector Kill — Similar to the balance test, this function allows a technician to disable injectors one by one. If disabling cylinder 2 or 5 causes no change in how the engine runs, it confirms that cylinder was already dead, pointing to the circuit fault.

Wiring & Ground Locations

• ECM (Engine Control Module) — Located in the engine compartment, at the front of the engine.. The ECM houses the injector driver circuits. The supply voltage for injectors 2 and 5 are paired on a single driver inside the ECM, making it the source of the control signal and fault detection.
• G103 / G104 — Primary engine grounds, typically located on the cylinder heads (e.g., front of passenger side head, rear of driver's side head).. The ECM and its injector driver circuits rely on a clean, solid ground connection. A loose or corroded ground at these primary locations can introduce electrical noise and voltage drops, potentially causing intermittent or false injector circuit codes.
• Injector Harness Chafe Points — Where the harness passes over/against the intake plenum, valve cover bolts, fuel lines, and the side of the cylinder head.. These are the specific locations documented in TSB #PIP4924D where the wiring harness is known to rub through, causing the open/short that triggers code P2152.

Real Owner Repair Stories

• acadiaforum.net user (2011 Acadia) — Engine misfiring, codes P2149 and P2152 stored simultaneously.
  ❌ Tried (didn't work) Initial diagnosis was unclear.
  ✅ What actually fixed it The cause was found to be the injector wiring harness chafed through where it passes over the top of the engine, consistent with TSB #PIP4924D.

OEM Part Supersession History

• 12614936 → 12621096 — Likely an update to improve wire insulation, routing, or connector quality to mitigate the known chafing issue.
• 12638530 (For LLT Engine) → 12669384 — Updated part for improved reliability or manufacturing process.
  Heads up: This injector is for the 2009-2011 LLT engine and is NOT compatible with the 2012-2014 LFX engine.

Model Year Variations Within This Range

• 2009-2011: These models use the 3.6L LLT V6 engine. This engine has an aluminum intake manifold, a Bosch ECM, and uses high-impedance fuel injectors (Part #12638530) with a resistance of 11-14 Ohms.
• 2012-2014: These models use the updated 3.6L LFX V6 engine. This engine has a composite intake manifold, integrated exhaust manifolds, a Delphi ECM, and uses low-impedance fuel injectors with a resistance of approximately 1.2-2.5 Ohms. The injectors are not interchangeable with the earlier LLT engine.