An EGR and O2 sensor restricted the engine along with a milder ECU. The VFB handles communication within the individual ECU and between ECUs. COBB Tuning was the first company to access the GT-R's encrypted ECU. They utilize parts which later became known as GT pistons, cams and engine ECU programs. Potential points of modification include intake, exhaust, fuel systems, transmissions, and the ECU. Most engine systems have idle speed control built into the ECU. Upgrade 16-bit to 32-bit ECU, some sensors changed. Typically the engine or main ECU responds at ID 7E8h. Engine performance increase comes largely from the long tube headers and a revised ECU. The armoured areas include the entire passenger cell, battery terminals and ECU (Engine Control Unit). Commands issued by the executing ECU software reaches the output controller must faster. Since 2003, the DNE variant comes with a new ECU and 3 oxygen sensors. Based on the input of the ECU, coils operate the inlet and outlet valves. Bits through represent the number of diagnostic trouble codes currently flagged in the ECU. Lambda probes provide feedback to an ECU.