🚨 Diagnostic Profile
Vehicle Make: BUICK
Technical Description: DI Low Resolution Circuit
This diagnostic trouble code relates to the Crankshaft Position (CKP) Low Resolution signal circuit used by the Engine Control Module (ECM) to synchronize fuel injection timing with piston position in Direct Injection (DI) engine systems. The ‘Low Resolution’ signal typically refers to a single-pulse-per-revolution signal (as opposed to the high-resolution multi-tooth reluctor signal) that helps the ECM identify Cylinder #1 Top Dead Center. A fault here can cause rough starts, stalling, misfires, or a no-start condition because the ECM cannot properly correlate camshaft and crankshaft position for direct injection pulse timing.
🚨 Repair Difficulty Tier
Difficulty Rating: Intermediate
This repair requires a capable bi-directional scan tool to view crank/cam correlation data in real time, along with a digital multimeter or lab scope to test wiring integrity and sensor waveform output. While physical replacement of the crankshaft position sensor is mechanically straightforward, accurately diagnosing whether the fault lies in the sensor, the wiring harness, or the ECM itself requires moderate automotive electrical diagnostic experience. This is not a simple bolt-on fix for beginners, but it does not require specialized module flashing in most cases (unless ECM replacement is necessary).
🛠️ Resolution Steps
Step 1: Preliminary Inspection
Begin with a visual inspection of the crankshaft position sensor connector and wiring harness near the engine block or bell housing area. Look for signs of damage such as melted connectors, chafed wiring from heat exposure, corrosion at the pins, or loose mounting of the sensor itself. Inspect the sensor’s mounting bracket to ensure it has not shifted, as the air gap to the reluctor wheel is critical for accurate signal reading. Also check for any oil contamination on the sensor tip, which is common in older DI engines with housing leaks.
Step 2: Diagnostic Verification
Connect a scan tool capable of displaying live Crankshaft Position and Camshaft Position correlation data. With the engine cranking (or running if possible), observe whether the Low Resolution signal is present, intermittent, or completely absent. Use a digital multimeter to check for proper reference voltage (typically 5V) and ground continuity at the sensor connector with the key on, engine off. For deeper analysis, a lab scope can be used to capture the actual waveform pattern of the low-resolution pulse to check for signal dropout, noise, or improper voltage swing. Confirm there are no additional correlation codes (such as Camshaft/Crankshaft Correlation faults) stored alongside this code, as multiple codes often point to a timing chain or tone wheel issue rather than just the sensor.
Step 3: Resolution & Reset Process
If wiring and connector are confirmed intact and voltage reference is correct, replace the Crankshaft Position Sensor (Low Resolution) with an OEM-spec replacement. Ensure proper torque specification and correct air gap seating during installation. After replacement, clear all stored Diagnostic Trouble Codes using the scan tool and perform a full crank relearn or ECM reset procedure as specified by GM service bulletins for the specific model year. Start the vehicle and monitor live data for several drive cycles to confirm the signal is now stable and no codes return. If the issue persists after sensor replacement, inspect the tone wheel/reluctor ring on the crankshaft for damaged teeth, and if wiring and sensor both test correctly, ECM reprogramming or replacement should be considered as a final step.
📦 Parts, Labor, and Budget Estimates
Required Components/Software: Crankshaft Position Sensor (Low Resolution), wiring harness pigtail repair kit (if needed), dealer-level scan tool (such as GM MDI/Tech2Win) for relearn procedures.
Average Component Price: $40 – $120 for the sensor itself; wiring repairs typically range $50 – $150 depending on harness complexity; ECM reprogramming/dealer software session can range $150 – $300 if required.
Estimated Labor Hours: 0.5 – 1.5 hours for diagnostic testing; 0.5 – 1.0 hour for sensor replacement; additional 0.5 hour if ECM relearn/reset procedure is required.