P0202 on 2009-2014 Buick Enclave: Injector Circuit Malfunction Causes & Fixes

What's Unique About the 2009-2014 Buick ENCLAVE

The 2009-2014 Buick Enclave uses the 3.6L V6 engine with direct injection (DI). On this transverse-mounted engine, Cylinder 2 is the middle cylinder on the front bank (Bank 2), which is closer to the radiator. General Motors has issued a Technical Service Bulletin (TSB #PIP4924D) for this engine platform concerning a range of injector circuit codes, including P0202. The TSB specifically advises technicians to inspect the fuel injector wiring harness for damage where it might rub against the intake plenum, valve cover bolts, or fuel lines, suggesting wiring issues are a known weak point on these vehicles. Due to the DI setup, replacing an injector is more involved than on a port-injected engine, requiring removal of the intake manifold.

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 misfire or running rough, especially at idle
• Poor acceleration and loss of power
• Reduced fuel economy
• Engine may hesitate or stall
• Noticeable smell of unburnt gasoline from the exhaust

Most Likely Causes

1. Faulty Fuel Injector (Cylinder 2) 🔴 High Probability → Shop Fuel Injector Direct injectors operate under high pressure and are subject to both internal electronic failure and clogging/failure from carbon buildup. The internal coil can fail, causing an open or short in the circuit.
   How to confirm: Measure the resistance of the injector with a multimeter (spec is typically 1.5-2.5 ohms for these DI injectors) and compare it to the other injectors; a significant difference or an open circuit (infinite resistance) indicates a failure. A more definitive test is to swap the cylinder 2 injector with another (e.g., cylinder 4) and see if the trouble code follows the injector (e.g., changes to P0204). This requires significant labor as the intake manifold must be removed. 🎬 See this step-by-step guide for replacing the fuel injectors.
   Typical fix: Replace the faulty fuel injector. It is often recommended to replace all injectors on the same bank (or all six) at the same time, especially on high-mileage vehicles.
   Est. part cost: $60-$160
2. Damaged Fuel Injector Wiring Harness 🟡 Medium Probability → Shop Engine Wiring Harness As noted in TSB #PIP4924D, the wiring harness on the 3.6L engine is known to chafe against engine components. Specific problem areas are against the intake plenum, at valve cover bolts, against fuel lines, and on the side of the cylinder head under the plenum.
   How to confirm: Visually inspect the wiring harness leading to the cylinder 2 injector for any signs of rubbing, melting, or broken wires, paying close attention to the areas mentioned in the TSB. Perform a 'wiggle test' on the harness with the engine running to see if it affects the misfire. Use a multimeter to check for continuity and voltage at the connector with the key on.
   Typical fix: Repair the damaged section of the wire or replace the injector wiring harness if damage is extensive.
   Est. part cost: $5-$50 for wire repair, $100+ for a new harness.
3. Poor Connection at Injector Connector ⚪ Low Probability Engine vibration can cause the electrical connector to become loose over time, or the terminals inside can become corroded or bent. The locking tab can also become brittle and break.
   How to confirm: Disconnect the connector for the cylinder 2 injector and inspect it for corrosion, bent pins, or a loose fit. Check that the locking tab engages securely. Apply dielectric grease to the connection before re-seating it firmly.
   Typical fix: Clean the terminals and ensure the connector is securely fastened. If the connector or its pigtail is damaged, it will need to be replaced.
   Est. part cost: $10-$30 for a new pigtail connector.

Rare But Worth Checking

• Faulty Powertrain Control Module (PCM): → Shop Engine Control Module (ECM) This is rare and should only be considered after all other possibilities (injector, wiring, connectors) have been thoroughly ruled out. The internal driver circuit for the injector can fail within the PCM.
• Clogged or Leaking Injector due to Carbon Buildup: While P0202 is an electrical code, severe carbon buildup on the tip of the direct injector can cause it to stick, leading to leaking (P02A1) or poor performance that can sometimes be misdiagnosed. A leaking injector was seen alongside P0202 in one owner's case.

Diagnosis Steps

1. Read the trouble codes with an OBD-II scanner to confirm P0202 and check for any other codes like P0302.
2. Locate cylinder 2. On the Enclave's transverse 3.6L engine, it is the middle cylinder on the bank closer to the radiator.
3. Visually inspect the wiring harness and connector for the cylinder 2 fuel injector. Look for obvious signs of damage, chafing, or loose connections, paying close attention to the areas mentioned in TSB PIP4924D: where the harness may contact the intake plenum, valve cover bolts, or fuel lines.
4. Use a noid light to test the injector connector. The light should flash when the engine is cranked or running, indicating the PCM is sending a signal. If it doesn't flash, or stays on constantly, there is a problem in the wiring or the PCM.
5. If the noid light flashes correctly, the issue is likely the injector itself. Turn off the engine and disconnect the injector.
6. Measure the electrical resistance (ohms) of the cylinder 2 injector and compare it to an adjacent injector. A reading that is significantly different (e.g., open loop/infinite resistance or a dead short) points to a bad injector.
7. For a definitive test, swap the cylinder 2 injector with an adjacent one (like cylinder 4). This requires removing the intake manifold. Clear the codes and run the engine. If the code changes to P0204, the injector is faulty. If the code remains P0202, the problem is in the wiring or PCM.
8. If the problem persists on cylinder 2 after the swap, perform a continuity test on the injector circuit wiring from the PCM connector to the injector connector to find any open or short circuits.
9. If the wiring and injector are confirmed to be good, the PCM may be at fault, which is a rare but possible cause.

Parts You'll Likely Need

• Fuel Injector (OEM #12638530, 12669384 (superseded)) — This is the most common component to fail in the circuit, either due to an internal short/open or mechanical failure from carbon buildup on this DI engine.
  Trusted brands: ACDelco (OEM), Bosch, Standard Motor Products (SMP)
  OEM price range: $110-$160
  Aftermarket price range: $60-$120
• Intake Manifold Gasket Set — Required for replacing the fuel injectors, as the upper intake manifold must be removed to access them.
  Trusted brands: Fel-Pro, ACDelco, Mahle
  OEM price range: $30-$50
  Aftermarket price range: $20-$40

Related Codes That Often Appear With This One

• P0302 — P0302 means "Cylinder 2 Misfire Detected." Since the P0202 code indicates a problem with fuel delivery to cylinder 2, a misfire is the direct result. The P0202 code is the cause, and P0302 is the symptom.
• P0201, P0203, P0204, P0205, P0206 — If multiple injector circuit codes are present, it strongly suggests a widespread wiring harness issue (like the chafing noted in TSB PIP4924D) or a problem with the power supply or ground common to all injectors.
• P0087 — P0087 indicates "Fuel Rail/System Pressure - Too Low." A severely malfunctioning or open injector circuit could potentially cause erratic readings in the fuel rail pressure, as seen in a documented repair case.

Technical Service Bulletins (TSBs) & Recalls

• PIP4924D: Mentions that a Service Engine Soon light with a misfire and various injector codes (including P0202) can be caused by the fuel injector wiring harness rubbing through or having internal wire opens. Specific inspection points include against the intake plenum, at valve cover bolts, and against fuel lines.

Platform-Specific Known Issues

• A known issue documented in GM TSB #PIP4924D involves the fuel injector wiring harness chafing against various engine components, leading to shorts or open circuits. This can trigger P0202 and other related injector codes.
• As a direct injection (DI) engine, the 3.6L LLT is susceptible to carbon buildup on the intake valves and injector tips. Severe buildup can impede injector function and cause related misfire or fuel trim codes.

Mechanic-Grade Diagnostic Values

• Fuel Injector Coil Resistance (3.6L LLT/LFX Direct Injector) — expected: 1.5 - 2.5 ohms. Failure: A reading of 0 ohms (short), infinity/OL (open), or a value significantly outside the expected range indicates a failed injector coil.
• High-Pressure Fuel System Pressure (at idle) — expected: 3.5 - 5.5 MPa (508 - 798 psi). Failure: Pressure that fails to meet the desired value on a scan tool can indicate an issue with the high-pressure fuel pump (HPFP) or rail pressure sensor, though this doesn't directly cause P0202.
• Low-Pressure Fuel System Pressure (at idle) — expected: 300 - 410 kPa (43 - 60 psi). Failure: Pressure below this range points to a weak in-tank fuel pump or clogged filter.
• Injector Pulse Width (at idle, comparative) — expected: ~2.45 milliseconds. Failure: While this varies, a pulse width for cylinder 2 that is drastically different from the other five cylinders on a scan tool can indicate a problem.
• Injector Inductive Kick Voltage — expected: >50 Volts. Failure: The absence of this voltage spike, which occurs when the injector's magnetic field collapses, is what the PCM detects to set the P0202 'circuit/open' code.

Scan Tool Commands That Help

• GDS2 / Tech2: Fuel Injector Balance Test / Active Fuel Injector Test (AFIT) — Use this function after verifying the electrical circuit is intact (noid light test passes). This command individually fires each injector and measures the corresponding drop in fuel rail pressure. It can identify a mechanically faulty, weak, or clogged injector that is not performing correctly, even if its electrical resistance is within spec.

Wiring & Ground Locations

• X160 Connector — Engine wiring harness connector.. If multiple injector codes (P0201, P0202, P0203, etc.) are present, GM service information suggests inspecting connector X160 for poor terminal tension or a missing terminal locking feature, as this can disrupt the power or control signals to a bank of injectors.

Real Owner Repair Stories

• YouTube user 'Prince' (2012 Buick Enclave AWD) — Persistent misfire code. After replacing plugs and coils, the misfire returned immediately accompanied by a large amount of white smoke from the exhaust.
  ❌ Tried (didn't work) Replacing spark plugs (worked temporarily), Replacing spark plugs and ignition coils
  ✅ What actually fixed it The owner identified the fuel injectors as the final possible cause. Upon removal, the old injectors showed significant carbon buildup on the tips. Replacing all six fuel injectors resolved the misfire and the white smoke issue.
• YouTube user 'Fix it Angel' (2010 Buick Enclave, 150k miles) — Engine running very rough, smelling of gas, smoke from exhaust. Codes P0087 (fuel rail pressure low), P0302 (cyl 2 misfire), and P02A1 (cylinder 2 - injector leaking) were present.
  ❌ Tried (didn't work) The video documents the diagnosis, not a list of failed prior attempts.
  ✅ What actually fixed it The diagnosis pointed towards a leaking fuel injector on cylinder 2. The video documents the successful repair by replacing the faulty fuel injectors. This case shows how a mechanical injector fault (leaking) can be linked to electrical and misfire codes.

OEM Part Supersession History

• 12638530 → 12669384 — Standard part revision and update by the manufacturer.
  Heads up: This part number is specific to the 2009-2011 Buick Enclave with the 3.6L LLT engine. It is NOT compatible with 2012-2014 models equipped with the LFX engine.

Model Year Variations Within This Range

• 2009-2011: These models are equipped with the 3.6L LLT V6 engine, which uses a Bosch ECM and fuel injector part number 12638530 (or its supersession).
• 2012-2014: Starting in 2012, the Enclave was equipped with the updated 3.6L LFX V6 engine. This engine features a different intake manifold, integrated exhaust manifolds in the cylinder heads, a Delphi ECM, and different fuel injectors (e.g., P/N 12663380). Parts and ECM pinouts are not interchangeable between LLT and LFX engines.