P0205 on 2021-2022 GMC Yukon: Cylinder 5 Injector Circuit Causes and Fixes

What's Unique About the 2021-2022 Gmc YUKON

For the fifth-generation GMC Yukon and its platform mates (Tahoe, Sierra, Escalade), the P0205 code is frequently linked to known issues with the engine wiring harness. General Motors has issued multiple Technical Service Bulletins (TSBs), including #22-NA-087 and #21-NA-149, that address wiring harness chafing and faulty injector connectors across all engine options. TSB 21-NA-149 notes the cause may be an engine wire harness clip that was left out during production, leading to an uncontrolled branch that can rub against sharp edges on the ECM/TCM bracket or other components.

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 shaking idle
• Engine misfire, which may feel like a shudder or stumble
• Reduced engine power and poor acceleration
• Hesitation when accelerating
• Decreased fuel economy
• Vehicle may stall or be hard to start

Most Likely Causes

1. Damaged Fuel Injector Wiring or Connector 🔴 High Probability Multiple GM TSBs (#22-NA-087, #21-NA-149) confirm the engine wiring harness is susceptible to chafing and damage. TSB 21-NA-149 explains this is often due to a harness clip being omitted during assembly, allowing the harness to vibrate against the ECM/TCM bracket, upper control arm, or shock tower bolt. For the 3.0L diesel, specific chafe points include the PCV hose clamp and on top of the generator. The injector connector itself is also a frequent failure point due to internal terminal fretting (vibration causing corrosion) or broken pins.
   How to confirm: Visually inspect the entire wiring harness leading to the cylinder 5 fuel injector. Pay close attention to known chafe points identified in TSB 21-NA-149. Perform a 'wiggle test' on the harness and connector with the engine running to see if it affects the idle. Use a multimeter to check for continuity and voltage at the injector connector. TSB 21-NA-149 also specifically directs technicians to check for poor terminal tension at the main sub-harness connector, X160.
   Typical fix: Repair the damaged section of the wire using heat-shrink butt connectors and anti-abrasion tape. If damage is at the connector, replace the injector connector pigtail. In cases of extensive damage, the entire engine sub-harness may need replacement.
   Est. part cost: $10-$120
2. Faulty Cylinder 5 Fuel Injector 🟡 Medium Probability TSB #22-NA-087 specifically notes that the fuel injector itself can be the cause, sometimes due to an internal failure of its coil winding. The bulletin often recommends replacing both the injector and its harness connector to ensure a complete repair, especially on the diesel engine where a broken terminal pin inside the injector connector is a known issue.
   How to confirm: After confirming the wiring is good, the easiest way to test the injector is to swap it with an injector from another cylinder (e.g., cylinder 1). Clear the codes and run the engine. If the code changes to P0201 (Cylinder 1 Injector Circuit), the injector is faulty. You can also test the injector's internal resistance with a multimeter. For gas engines, it should be within 12-16 Ohms. If it's outside this range, the injector has failed.
   Typical fix: Replace the cylinder 5 fuel injector. If working on a direct-injected engine (all Yukon options), this is a more involved job that requires removing the intake manifold and sometimes the fuel rail.
   Est. part cost: $75-$180

Rare But Worth Checking

• Powertrain Control Module (PCM) Fault: This is very rare. The PCM should only be considered after all other possibilities, including wiring and the injector itself, have been definitively ruled out. A PCM failure will typically cause multiple other trouble codes. TSBs explicitly warn against replacing the ECM unnecessarily.
• Poor ECM Ground Connection: A loose or corroded ground connection for the Engine Control Module can cause erratic voltage readings and faulty operation of the injector driver circuits. While not a primary cause, it's a crucial point to check if direct circuit tests are inconclusive. Key engine grounds are located on the cylinder heads and front radiator support.

Diagnosis Steps

1. Scan the vehicle for all stored trouble codes. Note if any other injector or misfire codes are present, including GM-specific symptom bytes like '-00'.
2. Perform a thorough visual inspection of the engine wiring harness, especially around the cylinder 5 injector. Look for signs of chafing, melting, or broken wires at common failure points like the ECM/TCM bracket, upper control arm, and shock tower bolt.
3. Inspect the electrical connector at the cylinder 5 injector for corrosion, damage, or loose pins. Look for a fine black or brown dust, which indicates fretting corrosion.
4. With the engine running, carefully wiggle the wiring harness and connector for cylinder 5. If the engine stumbles or the idle changes, a wiring fault is likely.
5. Disconnect the injector and use a noid light to test for a signal from the PCM. The light should flash steadily while cranking the engine. If it doesn't flash, or if it stays on continuously, there is a problem in the control circuit.
6. If the noid light test passes, check the internal resistance of the fuel injector using a multimeter. For gas engines, compare it to the OEM specification of 12-16 Ohms. For diesel, check against service manual specs.
7. If diagnostic tools are unavailable, swap the cylinder 5 fuel injector with one from another cylinder (e.g., cylinder 1). Clear the codes and see if the fault follows the injector (i.e., a P0201 code appears). If it does, the injector is bad. If P0205 returns, the problem is in the wiring or PCM.
8. Inspect the main injector sub-harness connector X160 for poor terminal tension or damage, as instructed by TSB 21-NA-149.
9. If all tests point to good wiring and a good injector, the issue may be a rare failure of the PCM's injector driver circuit.

Parts You'll Likely Need

• Fuel Injector Connector Pigtail (OEM #PT3739) — The connector itself is a common failure point due to internal resistance or damaged terminals from vibration. Replacing the pigtail is often the correct fix for a wiring issue at the injector.
  Trusted brands: ACDelco, Dorman
  OEM price range: $20-$40
  Aftermarket price range: $10-$25
• Fuel Injector (Gas V8) (OEM #12710481) — If the injector's internal coil has failed its resistance test, it must be replaced. This part number is a common replacement for the 5.3L and 6.2L engines.
  Trusted brands: ACDelco, Bosch, Delphi
  OEM price range: $120-$180
  Aftermarket price range: $70-$130
• Fuel Injector (3.0L Diesel) (OEM #55506244) — If the diesel injector has failed, it must be replaced. TSB #22-NA-087 identifies this part for replacement along with the harness for a complete repair.
  Trusted brands: ACDelco / GM Genuine Parts
  OEM price range: $100-$150
• 3.0L Diesel Fuel Injector Wiring Harness (OEM #40009605 (replaces 55513485, 55512145, 55510039, 55508024, 40009103)) — For the 3.0L Duramax engine, if the harness has multiple points of failure or significant damage, replacing the entire injector sub-harness is required. TSB 22-NA-087 calls for this part.
  Trusted brands: ACDelco / GM Genuine Parts
  OEM price range: $60-$120

Related Codes That Often Appear With This One

• P0305 — P0305 means 'Cylinder 5 Misfire Detected.' A fault in the injector circuit (P0205) prevents the cylinder from getting fuel, which directly causes a misfire. P0205 is the cause, and P0305 is the effect.
• P0201, P0202, P0203, P0204, P0206 — If multiple injector circuit codes appear at once, it strongly suggests a wiring harness issue at a point where the circuits for several injectors are bundled together, such as near connector X160 or at a major chafe point.

Technical Service Bulletins (TSBs) & Recalls

• 22-NA-087: Malfunction Indicator Lamp (MIL) Illuminated with DTC P0201, P0202, P0203, P0204, P0205, P0206 and/or P0216 Set
• 21-NA-149: Engine Wire Harness Chafing / IPC Gauges Sweep / IPC Warning Message / SES/Check Engine/MIL / No Start / No Crank / Runs Rough / Stalls / Reduced Engine Power / Various DTCs

Platform-Specific Known Issues

• TSB #22-NA-087: Specifically addresses MIL illumination with various injector codes (P0201-P0206) on the 3.0L LM2 Diesel. It directs technicians to replace BOTH the suspect fuel injector and the injector wiring harness due to potential for broken terminal pins inside the connector.
• TSB #21-NA-149: A comprehensive bulletin detailing multiple potential engine wiring harness chafe locations for 2019-2022 GM trucks and SUVs. It states a primary cause is a missing harness clip from production, allowing the harness to rub on the ECM/TCM bracket, upper control arm, and shock tower. It specifically calls out inspecting connector X160 for injector faults.

Mechanic-Grade Diagnostic Values

• Gas Engine Fuel Injector Resistance — expected: 12 - 16 Ohms. Failure: A reading significantly outside this range, or an open circuit (infinite resistance), indicates a failed injector coil.
• Gas Engine Injector Pulse Width (Live Data) — expected: Approximately 3.4 ms at idle. Failure: A value of 0 ms or an erratic reading for cylinder 5 while other cylinders are normal suggests a circuit or driver problem.
• Injector Circuit Voltage (Noid Light Test) — expected: A steady, flashing light while the engine is cranking or running.. Failure: No light, or a light that stays on continuously, indicates a fault in the wiring or the PCM's injector driver circuit.

Hidden / Shadow Codes Worth Checking

• P0205-00: The '-00' suffix is a GM-specific symptom byte that often accompanies the main DTC. While '-00' typically means no additional information is available, its presence on a professional scan tool confirms the fault is current and active. (see via GM GDS2/Tech2 or other professional-grade diagnostic scan tools.)
• Mode $06 Misfire Counts: This is not a code, but a diagnostic mode that shows raw data from onboard tests. A technician can monitor the misfire counter for cylinder 5 to see if it is incrementing, even if a P0305 has not been formally set yet. (see via A scan tool that supports Mode $06 diagnostics.)

Scan Tool Commands That Help

• GDS2 / Professional Scan Tool: Injector Balance Test / Cylinder Power Balance — This function allows a technician to disable injectors one by one to see the effect on engine RPM. If disabling cylinder 5 causes no change in RPM drop, it confirms that cylinder is not contributing, pointing towards the injector or its circuit.
• GDS2 / Professional Scan Tool: Injector Circuit Test — Some advanced scan tools can perform an automated electrical test on the injector driver circuit within the PCM, helping to rule out or confirm a rare PCM failure without extensive manual probing.

Wiring & Ground Locations

• Connector X160 — Main engine sub-harness connector. TSB #21-NA-149 directs technicians to inspect this connector for injector circuit faults.. This is a junction point for multiple injector circuits. Poor terminal tension or damage here can cause P0205 and potentially other injector codes simultaneously.
• G103 / G104 — Primary engine ground points. Typically located on the cylinder heads. One common location is the front of the passenger-side cylinder head, and another is the rear of the driver's-side cylinder head.. The ECM and its driver circuits rely on a clean, solid ground path. A loose or corroded ground at these locations can cause erratic voltage and trigger false injector circuit codes.
• ECM/TCM Bracket — On the driver's side of the vehicle, where the Engine Control Module and Transmission Control Module are mounted.. This is a primary chafe point identified in TSB #21-NA-149. The wiring harness can rub against a sharp edge on this bracket, damaging the wires for the cylinder 5 injector.

Real Owner Repair Stories

• YouTube user 'Pravbuilds' (2021 Chevrolet with L5P Duramax engine (similar injector connector design)) — Check Engine Light, 'Emission System Service' message, and a stored code P0205-00 for the cylinder 5 injector control circuit.
  ❌ Tried (didn't work) The technician noted from experience that extensive wiring tests are often fruitless, as the connector itself is the failure point '99% of the time'.
  ✅ What actually fixed it The problem was resolved by replacing the cylinder 5 injector pigtail connector using part number PT3739. An aftermarket version was sourced from Amazon and spliced into the harness with heat-shrink butt connectors.

OEM Part Supersession History

• 12687650, 12698484 → 12710481, which is now superseded by 12742701 — Revisions are common to improve reliability, materials, or manufacturing processes for direct injectors.
  Heads up: While these parts are generally interchangeable for the specified engines, always verify the correct part number with a VIN due to potential mid-year production changes.
• 55508024, 55510039, 55512145, 55513485, 40009103 → 40009605 — This extensive supersession history for the 3.0L Diesel injector harness indicates multiple revisions by GM to address the known chafing and connector issues.
  Heads up: The newest part number (40009605) should be used for all repairs to ensure the latest design improvements are incorporated.

Model Year Variations Within This Range

• 2022: Some parts suppliers note a specific exception for 2022 models, such as 'Except VEHICLE REQUIRES 2022 MODEL YEAR PARTS (AMK)'. This indicates that the 2022 mid-cycle refresh may have introduced different parts or wiring, and a VIN match is critical when ordering components to ensure compatibility.