P0273 on 2009-2010 Saturn VUE: Cylinder 5 Injector Circuit Low Causes and Fixes

What's Unique About the 2009-2010 Saturn VUE

On this specific generation of Saturn VUE with a V6 engine, there is a well-documented issue with the fuel injector wiring harness. General Motors issued a Technical Service Bulletin (TSB #PIP4924D) warning technicians that the harness is prone to rubbing against engine components like the intake plenum, valve cover bolts, or cylinder head. This known issue makes a wiring problem a more likely cause for P0273 than on other vehicles. The problem is common across many GM models that use the 3.6L V6 engine.

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
• Rough or shaky idle
• Engine misfire (may feel like a shudder or stumble)
• Poor acceleration and loss of power
• Reduced fuel economy
• Engine may run rich and have a fuel smell

Most Likely Causes

1. Chafed or Damaged Fuel Injector Wiring Harness 🔴 High Probability → Shop Engine Wiring Harness GM Technical Service Bulletin #PIP4924D specifically calls out this issue for the 2009-2010 VUE and its platform mates. The harness routing causes it to rub against the sharp edges of the intake manifold, valve covers, or fuel lines, leading to a short or open circuit. Cylinder 5 is on the rear bank, where the harness is tight and inspection is difficult.
   How to confirm: Carefully inspect the entire wiring harness leading to the cylinder 5 fuel injector. A borescope or inspection mirror may be necessary. Look for any signs of rubbing, exposed copper wires, or melting, particularly where the harness is secured to or passes over the engine.
   Typical fix: Repair the damaged section of wire with a new pigtail connector or by soldering and heat-shrinking. Secure the repaired harness away from the contact point using zip ties or re-routing to prevent future damage. Wrapping the area in protective loom or friction tape is also recommended.
   Est. part cost: $10-$30
2. Faulty Cylinder 5 Fuel Injector 🟡 Medium Probability → Shop Fuel Injector
   How to confirm: Swap the cylinder 5 injector with an adjacent one (e.g., cylinder 3). Clear the codes and drive. If the code changes to P0267 (Cylinder 3 Injector Circuit Low), the injector is bad. You can also test the injector's resistance with a multimeter; it should be within the manufacturer's specified range (typically 1.5-1.6 ohms for the 3.6L V6).
   Typical fix: Replace the faulty fuel injector. It's often recommended to replace the O-rings and seals at the same time. Given the labor to access the rear bank, some owners choose to replace all three rear injectors at once. 🎬 Watch: Step-by-step guide to replacing fuel injectors on this V6 engine.
   Est. part cost: $55-$120
3. Dirty or Clogged Fuel Injector ⚪ Low Probability → Shop Fuel Injector
   How to confirm: If the injector passes electrical tests but a misfire persists on cylinder 5, it may be mechanically clogged. A professional fuel injector cleaning service can confirm this.
   Typical fix: Replace the fuel injector. While professional cleaning is an option, replacement is often more practical for a single faulty injector, especially on a high-mileage vehicle.
   Est. part cost: $55-$120

Rare But Worth Checking

• Powertrain Control Module (PCM) Failure: → Shop Engine Control Module (ECM) This is the least likely cause. The internal driver circuit for the injector can fail. All other possibilities, especially wiring and the injector itself, should be exhaustively ruled out before considering PCM replacement, as it is expensive and requires programming.
• Corroded or Damaged Connector Pins: The electrical connector for the fuel injector itself, or the main engine harness connectors (like X160/X161 on similar platforms), can become corroded or have bent/loose pins, causing an intermittent low circuit fault. Inspect both the injector and harness side of the connector for any green or white corrosion or damage.

Diagnosis Steps

1. Scan the vehicle for all stored trouble codes. Note any other codes that appear with P0273.
2. Identify Cylinder 5. On the transverse V6, it is on the rear bank (firewall side), the middle cylinder. Bank 1 (rear) is 1-3-5, Bank 2 (front) is 2-4-6.
3. Perform a thorough visual inspection of the fuel injector wiring harness for cylinder 5, paying close attention to the areas mentioned in TSB #PIP4924D (against the intake, valve covers, fuel lines). A mirror and flashlight or a borescope will be very helpful.
4. Inspect the electrical connector at the cylinder 5 injector for corrosion, damage, or loose pins. Ensure the locking tab isn't broken, which can cause a poor connection.
5. If no wiring damage is found, use a noid light to check for a signal pulse at the injector connector. This confirms if the PCM is commanding the injector to fire.
6. If a signal is present, test the resistance of the fuel injector with a multimeter. A reading outside of the 1.5-1.6 ohm range for the 3.6L V6 indicates a faulty injector.
7. As a final confirmation, swap the cylinder 5 injector with another one (e.g., cylinder 3). If the trouble code follows the injector to the new cylinder (now P0267), the injector is confirmed to be the problem.
8. If the code remains on cylinder 5 after the swap, the issue is definitively in the wiring or the PCM.

Parts You'll Likely Need

• Fuel Injector Wiring Harness Pigtail — Due to the common chafing issue identified in TSB #PIP4924D, repairing the harness with a new connector pigtail is a frequent fix. This allows a fresh section of wire to be spliced in.
  Trusted brands: ACDelco, Dorman, GM Genuine Parts
  OEM price range: $20-$40
  Aftermarket price range: $10-$25
• Fuel Injector (OEM #12638530) — If the injector itself has failed electrically (open or shorted coil), it will need to be replaced. This part number is for the 3.6L V6.
  Trusted brands: ACDelco (OEM), Bosch, Delphi
  OEM price range: $176-$254
  Aftermarket price range: $55-$120

Related Codes That Often Appear With This One

• P0305 — P0305 means 'Cylinder 5 Misfire Detected'. P0273 is a specific electrical cause for the fuel injector problem that results in the misfire reported by P0305.
• P0205 — This code means 'Cylinder 5 Injector Circuit/Open'. It is very similar to P0273 and often points to the same root causes, like a broken wire or failed injector.
• P0274 — This is the opposite code, 'Cylinder 5 Injector Circuit High'. Seeing it alongside P0273 could indicate an intermittent wiring short that fluctuates between an open/low circuit and a short to power.
• P0261, P0264, P0267, P0270, P0276 — These are 'Circuit Low' codes for other cylinders. If multiple codes appear, it strongly suggests a larger wiring harness issue or a problem with a shared ground or power feed, rather than a single injector failure.

Technical Service Bulletins (TSBs) & Recalls

• PIP4924D: Warns of potential for the fuel injector wiring harness to rub through, causing open/short circuits and setting injector-related DTCs like P0273.

Platform-Specific Known Issues

• TSB #PIP4924D - Known Wiring Harness Chafing: TSB #PIP4924D documents a high likelihood of the fuel injector wiring harness rubbing through against engine components, causing various injector circuit codes, including P0273. The most common chafe points are the corner of the valve cover and the intake manifold support brackets.
• Cylinder #5 Location: On the transverse-mounted 3.5L and 3.6L V6 engines, the cylinder banks are split between the front (radiator side) and rear (firewall side). Bank 1 is the rear bank, and its cylinders are numbered 1, 3, and 5. Bank 2 is the front bank, with cylinders 2, 4, and 6. Therefore, cylinder #5 is the rearmost cylinder on the firewall side, making visual inspection and physical access very challenging without removing other components like the intake manifold.

Mechanic-Grade Diagnostic Values

• Fuel Injector Coil Resistance (3.6L LLT V6) — expected: 1.5 to 1.6 ohms. Failure: A reading near zero ohms indicates a short, while a significantly higher or infinite reading (OL) indicates an open circuit in the injector coil.
• Fuel Injector Coil Resistance (3.5L V6) — expected: 11 to 14 ohms. Failure: A reading significantly outside this range indicates a faulty injector coil.
• Fuel Pressure (Key On, Engine Off) — expected: 345-414 kPa (50-60 psi). Failure: Pressure below the specified range can indicate a weak fuel pump or a leak. Pressure should not drop more than 34 kPa (5 psi) in one minute.
• Fuel Pressure (Engine Idling) — expected: 296-310 kPa (43-45 psi). Failure: Pressure outside this range at idle suggests a problem with the fuel pressure regulator or pump.
• Injector Circuit Voltage (Key On, Engine Off) — expected: Approximately 12V (Battery Voltage) at the power feed wire for the injector.. Failure: Voltage below 11.5V points to excessive resistance in the power supply circuit or a wiring issue.

Scan Tool Commands That Help

• GM Tech2 / GDS2: Injector Balance Test (or Active Fuel Injector Test - AFIT) — This special function commands the PCM to fire each injector for a set duration and measures the corresponding drop in fuel pressure. It can identify a clogged or electrically weak injector that might otherwise pass a simple resistance test. This is a crucial step before removing the intake manifold.
• GM Tech2 / GDS2: Cylinder Power Balance — This function allows the technician to disable one cylinder at a time and observe the change in engine RPM. If disabling cylinder 5 causes little or no change in RPM, it confirms that cylinder is not contributing power, reinforcing the P0273 diagnosis.

Wiring & Ground Locations

• G105 / G106 — G105 is located at the left rear of the engine. G106 is on the top left front corner of the engine.. These are primary engine grounds. A loose or corroded connection at these points can introduce electrical noise and voltage drops, potentially causing intermittent injector circuit codes. While not a direct cause, they should be checked and cleaned as part of any electrical diagnosis.
• G108 — Located behind the left headlight assembly.. This ground point serves multiple components in the front of the engine bay. A poor connection here can affect various systems, and since the ECM is located in the left front of the engine compartment, ensuring this ground is clean and tight is important for stable ECM operation.
• ECM Connector X1 — The main 72-pin connector at the Engine Control Module (ECM), located in the left front of the engine compartment.. The control and supply wires for the fuel injectors run through this connector. Technicians can perform resistance and voltage tests directly at the ECM connector pins to test the entire injector circuit at once, ruling out wiring issues between the ECM and the injector. For the 3.6L, the Cylinder 5 injector control wire is typically a Light Green/White wire.

Real Owner Repair Stories

• Forum user on a related GM platform (GMC Acadia) (2009-2014 GMC Acadia with 3.6L V6) — Check Engine Light with injector circuit low codes (P0270 in this case, but same issue).
  ❌ Tried (didn't work) Replacing the fuel injector first.
  ✅ What actually fixed it The user found melted and bare wires inside the harness loom where it was rubbing against the engine. The final fix was to repair the damaged wires in the harness and re-secure it, which resolved the code. This directly confirms the issue described in TSB #PIP4924D.

OEM Part Supersession History

• 12602223 → 12638530, 12669384 — Part has been updated by GM over time for improved performance or manufacturing changes.
  Heads up: The 3.5L and 3.6L V6 engines use different types of fuel injectors (port vs. direct injection). Ensure the part number matches the specific engine in the vehicle. The 3.6L LLT engine uses part number 12638530 or its successors.