🚨 Diagnostic Profile
Vehicle/Equipment Make: BUICK
Technical Description: Injector Circuit Cylinder 6 Intermittent
This diagnostic code indicates an intermittent electrical fault within the fuel injector control circuit for cylinder 6. The Engine Control Module (ECM) is detecting an irregular signal pattern, open circuit condition, or short condition that does not persist consistently, making it more challenging to pinpoint than a constant fault. Common culprits include degraded wiring insulation, corroded connector pins, a failing injector solenoid winding, or a marginal ECM driver circuit.
🚨 Repair Difficulty Tier
Difficulty Rating: Intermediate
This repair requires the use of a quality automotive scan tool capable of reading live data streams and performing injector balance/power balance tests, along with a digital multimeter to check resistance and voltage drop across the injector circuit. While not requiring specialized module programming in most cases, proper diagnosis demands an understanding of pulse-width modulation signals and wiring schematics. A DIY enthusiast with intermediate electrical diagnostic experience could attempt this, but shops with an oscilloscope will have an easier time capturing the intermittent fault.
🛠️ Resolution Steps
Step 1: Preliminary Inspection
Begin with a visual inspection of the wiring harness leading to the cylinder 6 fuel injector. Look for signs of chafing, melted insulation (common near exhaust manifolds), rodent damage, or heat-stressed wiring. Inspect the injector electrical connector for corrosion, bent pins, or a loose locking tab. Wiggle-test the harness near the injector and at the ECM connector while watching for live data changes on a scan tool, as intermittent faults often reveal themselves under mechanical stress.
Step 2: Diagnostic Verification
Connect an OBD-II scan tool and monitor live data for injector pulse width and any pending/intermittent codes on cylinder 6 specifically. Perform an injector coil resistance test using a multimeter with the connector unplugged; compare the reading (typically 11-18 ohms for most GM-style injectors) against the other cylinders — a significant deviation indicates a failing injector. With the injector connected and the ignition on (or engine running), check for the reference voltage (typically close to battery voltage) at the injector connector, and verify the ECM is properly grounding the circuit by checking for a clean square-wave pulse width signal using an oscilloscope if available. Perform a cylinder power balance or injector buzz test to confirm cylinder 6 contribution to overall engine performance.
Step 3: Resolution & Reset Process
If wiring damage is found, repair or replace the damaged harness section using proper automotive-grade wire and heat-shrink butt connectors, ensuring no splices sit directly against hot engine components. If the injector itself tests out of specification, replace the fuel injector for cylinder 6, using new O-rings and a dab of lubricant during installation to avoid fuel leaks. Clear the diagnostic trouble codes using the scan tool and perform a relearn/idle relearn procedure if specified by the service manual. Conduct a test drive under varied conditions (idle, acceleration, highway speed) to confirm the intermittent fault does not reoccur, and recheck live data for consistent injector pulse width across all cylinders.
📦 Parts, Labor, and Budget Estimates
Required Components/Software: Replacement fuel injector (OEM or OEM-equivalent), wiring harness repair kit (butt connectors, heat shrink, GM-spec wire), dielectric grease for connector protection, OBD-II scan tool with live data/bi-directional capability, digital multimeter, optional oscilloscope for pulse-width verification.
Average Component Price: $45 – $150 per fuel injector (depending on engine type – V6 vs V8); $20 – $60 for wiring harness repair materials; no special dealer software/programming typically required for this repair.
Estimated Labor Hours: 1.0 – 2.5 hours for diagnosis (locating the intermittent fault can extend this), plus 0.5 – 1.5 hours for injector replacement or harness repair, depending on engine accessibility and cylinder 6 location (some V6/V8 configurations place rear cylinders deeper in the engine bay, increasing labor time).