P0206 on 2008-2009 Pontiac G8: Injector Circuit Malfunction Causes & Fixes

What's Unique About the 2008-2009 Pontiac G8

The Pontiac G8, a rebadged Holden Commodore, uses two distinct engines where cylinder #6 is in a different location. On the L76 6.0L V8, it's the third cylinder back on the passenger side. On the LY7 3.6L V6, it's the rearmost cylinder on the driver's side. This is critical for diagnosis. While the code's cause is usually a simple component failure, the Holden-based platform (VZ/VE Commodore) has documented cases where injector circuit codes can point to a rare but possible PCM failure. Owners of the Holden Commodore VF (a direct platform mate) have reported receiving codes P0206 and P0306, with dealers performing goodwill replacement of all 8 injectors, suggesting a known issue with the injectors themselves.

Symptoms You May Notice

• Check Engine Light is on
• Engine running rough or shaking (misfire)
• Poor acceleration and reduced engine performance
• Hesitation during acceleration
• Reduced fuel economy
• In severe cases, the engine may stall or be hard to start
• Smell of raw fuel from the exhaust
• Service StabiliTrak light may illuminate

Most Likely Causes

1. Failed Fuel Injector (Cylinder 6) 🔴 High Probability Fuel injectors are electro-mechanical parts with internal coils that can fail from heat cycles and age, leading to an open or shorted circuit. This is the most common reason for a P0206 code on higher mileage vehicles. Holden, the original manufacturer, has seemingly acknowledged injector issues on the related Commodore platform by replacing them under a goodwill warranty even after the original warranty expired.
   How to confirm: Swap the fuel injector from cylinder 6 with an adjacent cylinder (e.g., cylinder 4 on a V8 or V6). Clear the codes and drive the vehicle. If the code returns for the new cylinder (e.g., P0204), the injector is faulty. Alternatively, test the injector's internal resistance with a multimeter. It should be within 11-17 ohms. A reading of infinity (open) or near-zero (short) confirms a bad injector.
   Typical fix: Replace the faulty fuel injector. It is often recommended to replace them in sets if the vehicle has high mileage, especially if other injectors are original.
   Est. part cost: $55-$175
2. Wiring Harness or Connector Issue 🟡 Medium Probability Engine bay heat and vibrations can make wiring brittle and cause connectors to become loose or corroded over time. The wiring to the injector can chafe against other components, causing a short or open circuit. The locking tab on the connector can also become brittle and break, leading to a poor connection.
   How to confirm: Visually inspect the wiring harness leading to the cylinder 6 injector for any signs of melting, chafing, or breaks. Check the connector for loose pins, corrosion, or damage. Wiggle the harness with the engine running to see if it affects the misfire. A noid light test will show if the electrical pulse from the PCM is reaching the connector.
   Typical fix: Repair the damaged section of wire. If the connector is damaged, replace it with a new pigtail connector, which involves cutting the old plug off and splicing the new one in.
   Est. part cost: $15-$40

Rare But Worth Checking

• Powertrain Control Module (PCM) Failure: This is the least likely cause. The internal driver circuit for the #6 injector within the PCM can fail. On the related Holden VZ Commodore with the 3.6L V6, injector circuit fault codes are a known symptom of a failing ECU. This should only be considered after all other possibilities (injector, wiring) have been definitively ruled out through resistance and continuity tests. If the PCM is the cause, it will require replacement and programming specific to the vehicle's VIN.

Diagnosis Steps

1. Verify the Code: Use an OBD-II scanner to confirm that P0206 is the active code. Note any other codes, such as P0306, which is expected.
2. Locate Cylinder 6: This is a critical first step. For the L76 6.0L V8, cylinders are numbered 1-3-5-7 on the driver's side (front to back) and 2-4-6-8 on the passenger's side. Cylinder 6 is the third one back on the passenger side. For the LY7 3.6L V6, cylinders are 1-3-5 on the passenger side (front to back) and 2-4-6 on the driver's side. Cylinder 6 is the rearmost cylinder on the driver's side.
3. Check the Connector: Inspect the electrical connector on the #6 fuel injector. Ensure it's securely plugged in. Look for any signs of corrosion on the pins or damage to the connector body or locking tab.
4. Use a Noid Light: Disconnect the injector and plug in a noid light. Start the engine. The light should flash steadily, indicating the PCM is sending a pulse signal. If it flashes, the wiring and PCM are likely okay, and the injector is the prime suspect. If it does not flash or is steady on/off, there is a wiring or PCM issue.
5. Test the Injector Resistance: If you have a multimeter, disconnect the injector and set the meter to Ohms (Ω). Measure the resistance between the two terminals on the injector itself. It should typically read between 11 and 17 ohms. A reading of OL (Over Limit/infinity) means an open circuit, while a reading near 0 ohms means a short circuit. Either indicates a failed injector.
6. Perform the Injector Swap Test: If the noid light flashes and you don't have a multimeter, swap the #6 injector with one from another cylinder (e.g., #4). Clear the codes, run the engine, and see which code returns. If the code follows the injector (now P0204), you have a bad injector. If P0206 returns, the problem is in the harness or PCM.
7. Test the Circuit: If the noid light test fails, use a multimeter to check the wiring. With the key on (engine off), one pin on the connector should have ~12 volts (battery power). The other pin is the ground control from the PCM. Check for continuity (less than 1 ohm resistance) on the control wire from the injector connector back to the PCM connector (requires a wiring diagram).
8. Consider PCM Failure: If the injector and wiring have been proven to be good (injector has correct resistance, noid light doesn't flash, but wiring has continuity), the final possibility is a failed injector driver in the PCM. This is rare and requires professional diagnosis to confirm.

Parts You'll Likely Need

• Fuel Injector (L76 6.0L V8) (OEM #12576341) — This is the most common failure that triggers a P0206 code. The internal coil winding of the injector fails, causing an electrical open or short.
  Trusted brands: ACDelco, Bosch, GM Genuine Parts
  OEM price range: $65-$96
  Aftermarket price range: $40-$70
• Fuel Injector (LY7 3.6L V6) (OEM #12609418) — The V6 uses a different injector than the V8. Failure of the internal coil is the primary reason for replacement due to a P0206 code.
  Trusted brands: ACDelco, Bosch, Standard Motor Products
  OEM price range: $86-$90
  Aftermarket price range: $30-$60
• Fuel Injector Connector Pigtail (OEM #ACDelco PT2160) — The plastic connector and its locking tab can become brittle from heat and break, or the terminals can loosen, causing an intermittent connection that sets a P0206 code.
  Trusted brands: ACDelco, Dorman, Standard Motor Products (S-824), ICT Billet (WPINJ31X8)
  OEM price range: $25-$40
  Aftermarket price range: $8-$20

Related Codes That Often Appear With This One

• P0306 — P0306 means 'Cylinder 6 Misfire Detected'. Since P0206 indicates the cylinder 6 injector isn't firing correctly, the cylinder will misfire as a direct result. P0206 is the cause, and P0306 is the symptom.

Platform-Specific Known Issues

• Holden Commodore Injector Failures: On Australian forums for the Holden Commodore VE/VF (the vehicle the G8 is based on), there are multiple owner accounts of experiencing P0206 and P0306 codes. In one specific case with a 2014 VF SS, the owner reported a rough start-up condition that evolved into the check engine and ESP lights illuminating. The dealer diagnosed a bad cylinder 6 injector and, as a goodwill gesture, replaced all eight injectors free of charge, even though the vehicle was out of warranty. This suggests a known pattern of failure for these components.

Mechanic-Grade Diagnostic Values

• Fuel Injector Resistance (L76 6.0L V8) — expected: Approximately 12.5 Ohms. Failure: A reading of infinity (OL) indicates an open circuit. A reading near zero indicates a short circuit.
• Fuel Injector Resistance (LY7 3.6L V6) — expected: 11-17 Ohms (general spec, specific value not found, but similar GM V6 injectors fall in this range). Failure: A reading of infinity (OL) indicates an open circuit. A reading near zero indicates a short circuit.
• Injector Pulse Width at Idle (Warm Engine) — expected: Typically 1.5 ms - 4.5 ms. This value will fluctuate.. Failure: A consistently high pulse width on other cylinders may indicate the PCM is trying to compensate for the dead cylinder #6. A scan tool showing 0 ms for cylinder 6 confirms the PCM is not commanding it to fire.
• Injector Connector Voltage (Key On, Engine Off) — expected: One pin should show battery voltage (~12V). The other (control) pin should show 0V.. Failure: No voltage on the power pin indicates a problem with the power supply circuit. Voltage on the control pin with the key on indicates a short to voltage.

Scan Tool Commands That Help

• Tech 2 / GDS2: Injector Balance Test — This is a powerful diagnostic function to confirm a faulty injector without removing it. The tool commands each injector to fire for a precise duration while monitoring the corresponding drop in fuel rail pressure. If the pressure drop for cylinder 6 is significantly different from the others (e.g., much less drop), it confirms a flow issue with that injector. A difference of more than 3 PSI (20 kPa) between injectors is often considered a failure.
• Tech 2 / GDS2: Cylinder Power Balance — This test helps identify a weak cylinder by sequentially disabling one injector at a time and measuring the drop in engine RPM. If disabling cylinder 6 causes little or no change in RPM compared to other cylinders, it confirms that cylinder was not contributing power, which is expected with a P0206 code.

Wiring & Ground Locations

• G103 — In the engine compartment, on the ABS bracket (driver's side).. This is a major engine-related ground point. While not directly for the injectors, a poor connection here can cause unpredictable electrical issues in various engine systems.
• G106 (LY7 V6) / G111 (L76 V8) — On the right side (passenger side) of the engine block, near the middle.. This is a primary engine block ground. A loose or corroded connection here can directly impact sensor and actuator performance, including the fuel injectors.
• G107 (LY7 V6) — On the right side (passenger side) of the engine block, near the front.. Another critical engine block ground for the V6 engine. Corrosion or looseness can lead to intermittent electrical faults.
• Injector Harness Chafe Point — The harness that wraps around the rear of the driver's side fuel rail is a known chafe point on similar GM V8 platforms.. Vibration can cause the harness to rub against brackets or the engine itself, eventually wearing through the insulation and causing a short or open circuit on an injector wire.

OEM Part Supersession History

• 12602411 → 12609418 — Standard part revision and update by the manufacturer.
  Heads up: This part is for the LY7 3.6L V6 engine.

Model Year Variations Within This Range

• 2009.5: The mid-2009 model year update ('09.5) primarily added Bluetooth connectivity and removed the glove box light. There were no significant changes to the engine or fuel system related to this code.
• Late 2009: Some late 2009 models received a different water pump, upper radiator hose, and internal transmission parts to address a 2-3 shift flare issue. These changes are unrelated to the P0206 code.

Diagnostic Flowchart

Other Known Issues on This Vehicle

Issues unrelated to this code that are worth knowing about as an owner of this generation:

• Premature Timing Chain Stretch (3.6L LY7 V6) 🔴 High — Very common, often appearing between 50,000 and 120,000 miles. Triggers codes like P0008, P0017, P0019. (Ref: TSB #12-06-01-009F, Special Coverage #11340C (extended warranty to 10yr/120k miles for many models with this engine).)
• Failed Front Radius Rod / Control Arm Bushings 🟠 Medium — Extremely common failure point. Causes clunking, popping noises from the front suspension, and wandering steering feel. (Ref: Multiple TSBs exist for front-end noises, but no recall was issued for the arms themselves.)
• AFM/DOD Lifter Failure (6.0L L76 V8) 🔴 High — A known issue with Active Fuel Management (AFM) or Displacement on Demand (DOD) systems where lifters can collapse or fail, causing misfires, noise, and potential camshaft damage.
• Airbag System Recalls 🔴 High — All 2008-2009 G8s were subject to recall #11306 to reprogram the Sensing and Diagnostic Module due to an issue that could increase head injury risk for smaller front passengers in a crash. (Ref: Recall #11306)
• Brake Light Malfunction Recall 🟠 Medium — Certain 2008-2009 G8s were recalled because an incorrectly programmed brake pedal position switch could cause the brake lights to stay on continuously. (Ref: Recall #09046)

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: A used injector wiring harness pigtail from a junkyard is a viable option if the original connector is broken. It is much cheaper than a new harness section. A complete used engine wiring harness can also be a cost-effective solution if multiple connectors or wires are damaged, but inspect it carefully.

Donor-vehicle mileage cap: roughly under 100000 miles for the part to have meaningful remaining life.

What to inspect on the donor part:

• For a connector pigtail, ensure the plastic isn't brittle and the locking tab is intact.
• Check for any signs of corrosion (green or white powder) on the metal terminals inside the connector.
• Inspect the wires for at least 4-6 inches back from the connector to ensure they are not cracked, melted, or brittle.
• Avoid harnesses from vehicles that show signs of an engine fire or major fluid leaks in the area.

OEM-only on this vehicle (don't cheap out):

• Powertrain Control Module (PCM) - Aftermarket or improperly programmed used PCMs can cause a host of complex issues. Always use a new or professionally remanufactured unit programmed specifically to your vehicle's VIN.

Aftermarket brands forum-validated for this vehicle:

• Bosch (often the OEM supplier)
• ACDelco (GM's official brand)
• Standard Motor Products (SMP)

Brands owners have reported issues with on this vehicle:

• Unnamed, no-brand injector sets from online marketplaces should be avoided. While cheap, they often have inconsistent flow rates, leading to poor performance and other engine codes even if they resolve the P0206 electrical fault.

Real Owner Stories

Aggregated from forums and TSBs cited above. Mileages and costs reflect what owners reported in those sources.

Related OBD-II Codes

• P0306 — Cylinder 6 Misfire Detected. This code is almost always present with P0206, as the injector circuit fault prevents fuel delivery to cylinder 6, directly causing it to misfire.
• P0204 — Injector Circuit/Open - Cylinder 4. This code is likely to appear after performing a diagnostic swap of the suspected bad injector from cylinder 6 to cylinder 4. If P0204 appears, it confirms the injector is the faulty component.
• P0300 — Random/Multiple Cylinder Misfire Detected. If the root cause is a wiring harness issue that is chafing or has a loose connection, the fault could be intermittent or affect other injector circuits, leading to a more general misfire code.
• P0008 — Engine Positions System Performance Bank 1. This is not directly caused by the injector, but is a very common code on the 3.6L LY7 V6 G8 models, indicating a stretched timing chain, another major cause of poor engine performance on this platform.
• P0017 — Crankshaft Position - Camshaft Position Correlation Bank 1 Sensor B. Similar to P0008, this code points to the common timing chain stretch issue on the 3.6L V6 engine, a significant known issue for G8 owners that can cause misfire-like symptoms.

Frequently Asked Questions