🚨 Diagnostic Profile
Vehicle Make: BUICK
Code/Issue: Injector Circuit Cylinder 2 Intermittent
This fault indicates an intermittent electrical disruption in the fuel injector circuit for Cylinder 2. The Powertrain Control Module (PCM) is detecting irregular voltage or resistance patterns in the injector driver circuit, which can cause misfires, rough idle, or hesitation under load. Because the issue is intermittent, it often points to a wiring harness fault, a failing connector, or an injector solenoid that is beginning to degrade rather than a complete component failure.
🚨 Repair Difficulty Tier
Difficulty Rating: Intermediate
This repair requires a digital multimeter and a capable OBD-II scan tool with live data streaming and bi-directional control capability. While no advanced module programming is typically required unless the PCM itself needs reflashing, proper diagnosis demands knowledge of injector pulse-width testing, wiring harness tracing, and resistance value interpretation. DIY enthusiasts with intermediate automotive electrical experience can attempt this repair, but accurate fault isolation is critical to avoid unnecessary parts replacement.
🛠️ Resolution Steps
Step 1: Preliminary Inspection
Begin with a visual inspection of the Cylinder 2 injector connector and surrounding wiring harness. Look for signs of corrosion, melted insulation, chafing against engine components, or a loose/partially disengaged connector lock. Wiggle-test the harness near the injector and at the PCM connector while monitoring for any changes in idle quality, as intermittent faults often reveal themselves under mechanical stress. Inspect the engine harness routing for rubbing against brackets, exhaust manifold heat shields, or other moving parts that could cause insulation breakdown over time.
Step 2: Diagnostic Verification
Connect an OBD-II scan tool capable of live data streaming and monitor injector pulse-width and fuel trim values for Cylinder 2 compared to adjacent cylinders. Significant deviation in short-term or long-term fuel trim on Cylinder 2 suggests an inconsistent injector signal. Next, use a digital multimeter to check resistance across the injector solenoid terminals (typically between 11-16 ohms for most Buick port injectors, consult service manual for exact spec). With the connector disconnected, check for continuity and proper voltage reference (usually battery voltage) at the harness side connector with the key on. Perform a wiggle test on the harness while watching live voltage/resistance readings to catch the intermittent dropout in real time. If available, use the scan tool’s bi-directional controls to command an injector buzz test to confirm consistent actuation.
Step 3: Resolution & Reset Process
If the injector itself tests within acceptable resistance specs and shows no physical damage, the issue is likely isolated to the wiring harness or connector. Repair or replace the damaged harness section using OEM-spec wiring and weatherproof connectors, ensuring proper strain relief to prevent recurrence. If the injector fails resistance or activation testing, replace the injector solenoid unit directly. After repair, clear the stored Diagnostic Trouble Codes (DTCs) using the scan tool and perform a PCM idle relearn procedure if applicable to the model year. Road test the vehicle under varied load conditions to confirm the intermittent fault does not return, and recheck live fuel trim data to verify Cylinder 2 is now balanced with the other cylinders.
📦 Parts, Labor, and Budget Estimates
Required Components/Software: Fuel injector (Cylinder 2) if solenoid fails testing, injector wiring harness pigtail/connector repair kit, dielectric grease, OBD-II scan tool with bi-directional control, digital multimeter.
Average Component Price: $45–$120 for a single replacement injector (depending on engine type); $15–$40 for a harness repair/connector kit. No dealer module programming is typically required for this specific fault unless deeper PCM-related issues are found.
Estimated Labor Hours: 0.5–1.0 hour for diagnostic testing; 0.5–1.5 hours for injector or harness repair/replacement depending on engine accessibility. Total shop time typically ranges from 1.0 to 2.5 hours.