Does tuning the engine in an older Audi with an automatic transmission always require reprogramming the transmission as well? This Audi A6 C6 3.0 TDI provided a case-specific test while retaining the transmission control unit’s software and torque limits.

Before the work, the dynamometer recorded 208 hp and 421 Nm, compared with nominal figures of about 233 hp and 450 Nm. Diagnostics found that the previous software configuration had been changed, while the particulate filter was still physically installed and was not regenerating. This could increase exhaust restriction and limit engine output.

After the software was corrected and the filter-related issue was addressed, the engine was calibrated without reprogramming the automatic transmission. The dyno recorded 265 hp and 553 Nm. During the road test, the owner reported no jerking or discomfort, and the shifts were smooth.

This result applies to this particular car and its condition at the time of testing. It does not guarantee that every automatic transmission can handle the same power increase; transmission condition, engine calibration and retained torque limits all matter.