Drivers first notice the check‑engine light illuminated on the instrument panel. In addition, the engine may run unevenly at idle, producing a choppy or low‑rpm feel. When the throttle is applied, a hesitation or “lugging” sensation is common, especially during quick accelerations from a stop. Power loss can be evident on uphill climbs or when trying to pass another vehicle; the engine seems reluctant to increase speed despite the driver’s input. These symptoms persist until the calibration is relearned or the underlying module issue is corrected.
The engine control module (ECM) stores a fuel‑delivery map that the injection pump must learn during the initial start‑up or after a service reset. If the ECM’s flash memory is corrupted, the pump never receives a valid map, triggering P2674.
The pump and ECM exchange data over a high‑speed CAN or dedicated serial line. Corroded pins, broken wires, or a faulty connector can interrupt this exchange, preventing the calibration sequence from completing.
Modern injection pumps contain an internal microcontroller that executes the calibration algorithm. Internal component failure—such as a burned MOSFET or damaged voltage regulator—means the pump cannot acknowledge the ECM’s request, leaving the calibration “unlearned.”
The calibration routine requires a stable 12.6 V supply. A weak battery or a momentary voltage dip (e.g., when accessories are switched on) can abort the process, causing the ECM to set P2674.
Clearing the ECM’s memory after a major repair, fuel‑system service, or battery disconnect erases the learned calibration. If the technician does not run the manufacturer‑specified relearn procedure, the code reappears.
– Connect an OBD‑II scan tool capable of manufacturer‑specific functions. Record the freeze‑frame parameters (engine speed, load, fuel trim) to confirm the conditions under which the fault manifested.
– Measure resting voltage; it should be 12.6 V or higher. Perform a load test to ensure the battery can sustain >13.5 V during cranking. Replace or recharge if voltage is low, then repeat the scan.
– Locate the pump‑ECM harness. Check for corrosion, frayed conductors, or loose pins. Use a multimeter to confirm continuity and proper resistance values as specified in the service manual.
– Using the OEM scan tool, select “Injection Pump Calibration” or “Fuel‑Pump Learning.” Follow the step‑by‑step prompts: engine off, key on, pump activation, and idle stabilization. The tool will indicate success or failure.
– Monitor pump‑output pressure, fuel‑trim percentages, and ECM‑pump communication flags. Values outside manufacturer tolerances suggest a deeper module fault.
– Run a bidirectional test on the CAN bus or dedicated pump line. Errors such as “no response” or “invalid data” point to a faulty ECM or pump controller.
– If the pump’s internal controller shows no voltage on its power rail, or the ECM repeatedly fails the communication test after wiring repairs, replacement is the prudent path.
Cost Estimates
If the diagnostic sequence repeatedly indicates a loss of communication or the pump’s internal controller does not respond to voltage, repairing the module is often a temporary fix. Repeated failures usually stem from internal board damage that cannot be reliably restored. In such cases, installing a new, VIN‑matched control module eliminates the root cause and restores full calibration capability.
Flagship One’s Expertise
Modern control modules integrate engine management, security, and immobilizer functions, making precise programming essential. Flagship One specializes in VIN‑matched control modules, providing a plug‑and‑drive solution backed by a comprehensive warranty. Each replacement unit is pre‑programmed to your vehicle’s exact specifications before it ships, ensuring seamless integration and eliminating dealer‑only reflash delays.
Service Recommendation: Most issues related to this fault are diagnosed and corrected through inspection, wiring repair, and calibration rather than module replacement. For modules not typically replaced through aftermarket suppliers, diagnosis and repair should be performed by a certified automotive technician with access to factory service information and tooling.
The engine will run, but reduced power and hesitation can affect acceleration, especially in traffic. Driving is possible for short distances, but you should schedule a diagnostic scan and calibration relearn as soon as practical to avoid potential stalling.
Replacement units vary by production date and software version, so the correct module is matched by VIN before programming. Expect a parts cost of $800‑$1,200 plus $150‑$250 labor for installation and VIN programming.
A battery that cannot maintain at least 12.6 V during the calibration routine can abort the learning process, leading to P2674. Test the battery’s voltage and load capacity; if it falls below specifications, replace it before re‑attempting the calibration.
Clearing the code erases the stored fault but does not fix the underlying issue. The recurring P2674 suggests that the calibration never successfully completed, typically due to communication loss or internal module failure. A full diagnostic, including wiring inspection and a calibrated relearn, is required.
While a mechanically failed pump can cause other codes, P2674 specifically points to a calibration learning problem. If the pump’s internal controller is defective, the control module replacement is the appropriate remedy because the pump’s electronics are integrated into the module’s operation.