A 2021 Mazda CX-9 rolled into a workshop recently with a P061D code, a severe hesitation issue, and an owner terrified of a $6,000 dealership bill. The vehicle would start, hesitate, and sometimes shut off completely. Pumping the gas and letting it warm up allowed it to drive, but the hesitation remained.
The Relationship Between P0171 and P061D
When analyzing the scan data, the shop found P061D (Internal Control Module Engine Torque Performance) alongside P0171 (System Too Lean, Bank 1). Our diagnostic engine looked at both codes together. The P0171 points to excessive oxygen in the exhaust. The ECM adds fuel to compensate, but the unmetered air throws off the load calculation. That discrepancy between the calculated engine load and expected torque output triggers the P061D.
The platform ranked an intake system vacuum leak as the 90 percent likely root cause. Unmetered air entering past the MAF sensor on the 2.5L Turbo engine forces this exact lean condition and torque calculation failure. We recommended a smoke test of the intake system, listening for hissing, and checking the PCV hoses, turbo inlet pipe, intercooler boots, and intake manifold gaskets.
High-Pressure Fuel System Degradation
If the intake is sealed, the next logical step is fuel delivery. The system ranked high-pressure fuel pump or fuel injector degradation at an 85 percent probability. These GDI engines demand massive fuel rail pressure. If the high-pressure fuel pump cannot maintain that pressure, or if the injectors develop a poor spray pattern, the engine starves. This fuel restriction creates the lean condition for P0171 and immediately prevents the engine from hitting its commanded torque, setting the P061D. The platform directed the technician to monitor fuel rail pressure with a scan tool, run an injector balance test, and inspect the high-pressure pump cam follower.
Airflow Measurement and EVAP
We also flagged a contaminated MAF sensor at 75 percent probability. If the MAF under-reports airflow, the ECM injects less fuel, leaning out the mixture and scrambling the torque math. Checking live data and inspecting the connector is a fast way to rule this out. Trailing at 65 percent was a stuck EVAP purge solenoid valve. A leaking purge valve acts as a vacuum leak, pulling unmetered air directly into the intake manifold.
Next Steps
Diagnosing two interacting codes requires looking at the symptoms as a complete system rather than swapping parts for each code individually. Do you see a lot of these torque performance codes hiding behind simple lean conditions in your bays?