P0202 on 2021-2024 GMC Yukon: Injector Circuit Malfunction Causes and Fixes

What's Unique About the 2021-2024 Gmc YUKON

For the 2021-2024 GMC Yukon and its sister platforms (Tahoe, Escalade, Silverado/Sierra), General Motors has issued multiple Technical Service Bulletins (TSBs) that directly address code P0202. These bulletins, particularly for the 3.0L Duramax diesel engine, indicate a known issue with both the fuel injectors and their wiring harnesses. TSB #22-NA-087 specifically identifies the cause as a "broken terminal pin inside the #2 injector harness connector" and mandates replacing both the injector and harness. Additionally, a GM TechLink article warns of potential engine wiring harness chafing on these T1 platform vehicles, which can cause injector circuit codes by damaging wires near the generator or other engine components. This pattern of failures and official repair procedures makes it a well-documented issue for this specific vehicle generation.

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 in severe cases)
• Rough or unstable idle
• Engine hesitation or stumbling during acceleration
• Reduced engine power and performance
• Decreased fuel economy
• A noticeable fuel smell if the injector is stuck open
• Engine may be hard to start or require extended cranking

Most Likely Causes

1. Faulty Cylinder 2 Fuel Injector Wiring Harness or Connector 🔴 High Probability Multiple GM TSBs (#PIE0802A, #22-NA-087) explicitly identify the wiring harness and connector as a primary failure point. TSB #22-NA-087 states the cause is often a "broken terminal pin inside the #2 injector harness connector." A real-world owner report for a 3.0L Duramax confirms the connector for an adjacent cylinder (#4) failed at 115k miles due to heat from the nearby EGR pipe, causing the connection to become loose.
   How to confirm: Visually inspect the connector and wiring for any signs of damage, melting, or corrosion. Perform a 'wiggle test' on the connector while the engine is idling to see if it affects the misfire. Use a noid light to confirm if the electrical pulse from the PCM is reaching the connector. If the light doesn't flash, the problem is upstream in the wiring or PCM.
   Typical fix: Replace the fuel injector connector pigtail or the entire injector sub-harness. Per TSBs, this should be done in conjunction with replacing the injector itself. The harness for the 3.0L diesel has been updated by GM.
   Est. part cost: $30-$60
2. Failed Cylinder 2 Fuel Injector 🔴 High Probability TSBs confirm that the injectors themselves are a common failure item. A loose or faulty connector can cause arcing that damages the electrical pins on the injector body, leading to internal failure. The internal coil winding of the injector can also fail on its own, creating an open or shorted circuit that the PCM detects.
   How to confirm: After confirming the wiring is good with a noid light, the easiest way to confirm a bad injector is to swap it with an injector from another cylinder (e.g., swap cylinder 2 with cylinder 4). Clear the codes and run the engine. If the code changes to P0204, the injector is confirmed to be faulty. You can also test the injector's resistance with a multimeter. Compare the reading to other injectors; a significantly different reading indicates a bad injector. For the 5.3L V8, a healthy injector should read around 13.5 ohms.
   Typical fix: Replace the fuel injector. Per TSB #22-NA-087, it is highly recommended to also replace the wiring harness/pigtail at the same time to prevent the code from returning. For the 3.0L Duramax, the new injector's flow rate must be programmed into the ECM using a bidirectional scan tool.
   Est. part cost: $80-$250
3. Faulty Powertrain Control Module (PCM) ⚪ Low Probability
   How to confirm: This should only be considered after the injector and wiring have been definitively ruled out. A professional technician with advanced diagnostic tools would need to verify the failure of the injector driver circuit inside the PCM. A forum user reported having their ECM replaced, only for the problem to persist, indicating this is often a misdiagnosis.
   Typical fix: Replace and reprogram the PCM. This is an expensive repair and requires specialized tools.
   Est. part cost: $800-$1500

Rare But Worth Checking

• Chafed Engine Wiring Harness:

Diagnosis Steps

1. Scan the vehicle's computer to confirm P0202 is the active code and check for any other related codes like P0302.
2. Perform a thorough visual inspection of the cylinder 2 fuel injector connector and its wiring. Look for any broken wires, loose pins, or signs of melting or corrosion. Pay close attention to the harness routing near heat sources or sharp edges.
3. Disconnect the injector and plug in a 'noid light'. Crank the engine. The light should flash steadily. If it does not flash, the problem is in the wiring or the PCM. If it does flash, the PCM and wiring are likely good, and the injector is the prime suspect.
4. If the noid light test passes, measure the resistance of the fuel injector with a multimeter. For the 5.3L V8, expect a reading around 13.5 ohms. Compare the reading to the other injectors. A significant deviation or an open circuit (infinite resistance) indicates a failed injector.
5. For a definitive test, swap the cylinder 2 injector with one from another cylinder (e.g., cylinder 4). Clear the codes, run the engine, and see if the fault code moves to P0204. If it does, the injector is bad. If P0202 returns, the problem is in the wiring.
6. Based on TSB guidance for this vehicle, if either the injector or wiring is found to be at fault, replace both the injector and the connector/harness to ensure a reliable repair. For the 3.0L Duramax, the flow rate from the new injector must be programmed into the ECM with a scan tool.

Parts You'll Likely Need

• Fuel Injector (3.0L LM2 Diesel) (OEM #55506244) — This is one of the two most common failure points, as confirmed by multiple TSBs. The internal electronics of the injector fail or the pins get damaged from a loose connector. Note: This part is for the LM2 engine used in 2021-2024 Yukon/Tahoe SUVs and is not compatible with the newer LZ0 engine.
  Trusted brands: ACDelco, GM Genuine Parts
  OEM price range: $210-$250
  Aftermarket price range: $150-$200
• Fuel Injector (5.3L/6.2L Gas V8) (OEM #12723434) — The gas engines also suffer from injector failures, though the diesel issue is more widely documented by TSBs. Failure of the internal coil is the typical cause.
  Trusted brands: ACDelco, GM Genuine Parts
  OEM price range: $100-$150
  Aftermarket price range: $70-$120
• Fuel Injector Wiring Harness (3.0L LM2 Diesel) (OEM #40009605) — TSB #22-NA-087 explicitly calls for replacing this harness along with the injector due to a known issue with broken terminal pins inside the connector. This is the updated part number, superseding the original 55513485.
  Trusted brands: GM Genuine Parts
  OEM price range: $40-$60
  Aftermarket price range: N/A
• Fuel Injector Connector (Pigtail for V8) (OEM #PT2160) — If only the connector is damaged on a V8 engine, a pigtail can be spliced in. The plastic can become brittle and the terminals can lose connection, causing the P0202 code.
  Trusted brands: ACDelco, Standard Motor Products, Dorman
  OEM price range: $30-$50
  Aftermarket price range: $20-$40

Related Codes That Often Appear With This One

• P0302 — This code means 'Cylinder 2 Misfire Detected.' It's commonly seen with P0202 because if the injector circuit has a fault, the injector cannot deliver fuel, which directly causes the cylinder to misfire.
• P0201, P0203, P0204, etc. — TSB #22-NA-087 notes that multiple injector circuit codes can appear at once. A GM TechLink article suggests this often points to a larger issue, such as a damaged section of the main engine wiring harness affecting several injector circuits, rather than multiple individual injector failures.

Technical Service Bulletins (TSBs) & Recalls

• PIE0802A: Recommends replacing the wire harness and affected fuel injector for DTC P0202.
• 22-NA-087: Advises replacing the fuel injector and wiring harness for DTCs P0201-P0206 on diesel models.
• PIE0802: Engineering investigation into DTC P0202.
• PIE0791B / PIE0791A: Engineering investigation into DTCs P0202 and P0203.
• PIP5891C: Notes faulty injectors as the cause for P020x codes on V8 gas engines and warns against replacing the ECM.

Platform-Specific Known Issues

• TSB #22-NA-087: This is the key bulletin for 2021-2022 models with the 3.0L Duramax Diesel engine (LM2). It addresses MIL illumination with codes P0201-P0206. The cause is identified as a "broken terminal pin inside the #2 injector harness connector." The official fix is to replace BOTH the fuel injector (P/N 55506244)

Mechanic-Grade Diagnostic Values

• 5.3L V8 Fuel Injector Resistance — expected: Approximately 13.5 ohms. Failure: A reading that is significantly different from other injectors, or an open (infinite) or shorted (near zero) reading.
• General Fuel Injector Resistance (Diesel/Gas) — expected: 10 - 16 ohms. Failure: A reading outside this range, or one that deviates significantly from the other injectors on the engine.
• Injector Circuit Voltage (Key On) — expected: 12V (Battery Voltage) on the power supply wire (typically Pink on GM vehicles).. Failure: Low or no voltage indicates a problem in the power supply circuit from the fuse block.

Scan Tool Commands That Help

• GM GDS2 (Global Diagnostic System 2): Fuel Injector Balance Test — This automated test is used when a P0202 code is present but the cause is not obvious from initial wiring checks. The tool commands each injector to open momentarily while the engine is running and measures the corresponding drop in fuel rail pressure. A cylinder that shows a significantly different pressure drop than the others points to a faulty injector or a flow problem.
• GM GDS2 (Global Diagnostic System 2): Injector Programming / Flow Rate Programming — This function is required after replacing a fuel injector on the 3.0L Duramax diesel engine. The new injector has a specific flow rate code printed on it that must be entered into the ECM to ensure accurate fuel delivery and engine performance.
• GM GDS2 (Global Diagnostic System 2): Output Controls / Actuation Tests — This allows a technician to manually command the cylinder 2 injector driver circuit on and off to listen for a 'click' from the injector solenoid. This can help isolate whether the fault is in the control circuit or the injector itself, similar to a noid light test but performed via software.

Wiring & Ground Locations

• Cylinder 2 Injector Control Wire — Runs from the cylinder 2 fuel injector connector to the Engine Control Module (ECM).. This wire carries the ground signal from the ECM that fires the injector. Based on GM wiring conventions, this is likely a Light Green/Black wire. A break or short in this wire is a direct cause of P0202.
• ECM Connector X2, Pin 10 — On the main Engine Control Module (K20). The ECM is typically located in the engine bay.. This is the specific pin on the ECM that controls the cylinder 2 injector, based on common GM pinouts. Technicians can test for continuity from this pin to the injector connector to verify the integrity of the control wire.
• G103 / G104 Engine Grounds — Common GM ground points are located on the cylinder heads (often rear, near the firewall) or on the engine block itself. G103 is often cited as being on the cowl/firewall, grounding the BCM and other modules that communicate with the ECM.. A poor engine or ECM ground can cause a host of electrical issues, including erratic sensor readings and incorrect voltage on control circuits, which could potentially trigger an injector circuit fault.

Real Owner Repair Stories

• Reddit user in r/gmcsierra (2021 GMC Sierra with 3.0L Duramax, 115,000 miles) — Check engine light with codes P0204 and P0304 (Cylinder 4 Injector Circuit and Misfire).
  ❌ Tried (didn't work) Limping the truck along using dielectric grease on the connector as a temporary measure.
  ✅ What actually fixed it The user replaced the entire fuel injector wiring harness (P/N 40009605). They noted that the #4 connector, which is located just under the hot EGR pipe, had become loose over time, causing the fault. This aligns perfectly with the TSBs that point to connector/harness failure.

OEM Part Supersession History

• 55513485 → 40009605 — This is the fuel injector wiring harness for the 3.0L LM2/LZ0 diesel engine. The part was likely updated to improve durability or resolve the known connector pin issue described in TSBs.

Model Year Variations Within This Range

• 2021-2024: The 3.0L Duramax diesel engine in the GMC Yukon and other GM SUVs (Tahoe, Suburban, Escalade) is the LM2 version for all model years from 2021 through 2024. The updated LZ0 engine was introduced in 2023, but only for the Silverado and Sierra pickup trucks.
• 2021-2024: The fuel injectors for the LM2 diesel (P/N 55506244) and the LZ0 diesel are NOT interchangeable. The LZ0 uses different injectors to work with its new steel pistons and combustion bowl design. Ordering the wrong injector for the engine will cause performance issues. Since 2021-2024 Yukons exclusively use the LM2, P/N 55506244 is the correct part.