Editing Active Fuel Management (section)

==Second generation==
In 2004, the electronics side was improved greatly with the introductions of Electronic Throttle Control, electronically controlled transmissions, and transient engine and transmission controls. In addition, computing power was vastly increased. A [[solenoid]] control valve assembly integrated into the engine valley cover contains solenoid valves that provide a pressurized oil signal to specially designed hydraulic roller lifters provided by Eaton Corp. and Delphi. These lifters disable and re-enable exhaust and intake valve operation to deactivate and reactivate engine cylinders [https://web.archive.org/web/20061029082032/http://www.gm.com/company/onlygm/fuel/engine.html]. Unlike the first generation system, only half of the cylinders can be deactivated. It is notable that the second generation system uses [[engine oil]] to hydraulically modulate engine valve function. As a result, the system is dependent upon the quality of the oil in the engine. As anti-foaming agents in engine oil are depleted, air may become entrained or dissolve in the oil, delaying the timing of hydraulic control signals. Similarly engine oil [[viscosity]] and cleanliness is a factor. Use of the incorrect oil type, i.e. [[Society of Automotive Engineers|SAE]] 10W40 instead of SAE 5W30, or the failure to change the engine oil or oil filter at factory recommended intervals, can also significantly impair system performance.{{Citation needed|date=April 2008}}

In 2001, GM showcased the 2002 [[Cadillac Cien]] [[concept car]], which featured [[Cadillac Northstar engine|Northstar]] XV12 engine with Displacement on Demand. Later that year, GM debuted [[Opel Signum]]² concept car in [[Frankfurt Auto Show]], which uses the global XV8 engine with displacement on demand. In 2003, GM unveiled the [[Cadillac Sixteen]] concept car at the Detroit Opera House, which featured an XV16 concept engine that can switch between 4, 8, and 16 cylinders.

On April 8, 2003, General Motors announced this technology (now called Active Fuel Management) to be commercially available on 2005 [[GMC Envoy]] XL, Envoy XUV and [[Chevrolet TrailBlazer]] EXT using optional [[GM small-block engine#5300|Vortec 5300]] V8 engine. GM also extended the technology on the new [[GM High Value engine#LZ8|High Value ''LZ8'']] V6 engine in the [[Chevrolet Impala]] and [[Chevrolet Monte Carlo|Monte Carlo]] as well as the 5.3L V8 LS4 engine in the last generation Chevrolet Impala SS, Monte Carlo SS and Pontiac Grand Prix GXP.  In both designs, half of the cylinders can be switched off under light loads.

On July 21, 2008, General Motors unveiled the production version of the [[Fifth-generation Chevrolet Camaro|2010 Chevrolet Camaro]]. The Camaro SS with an automatic transmission features the [[GM LS engine#L99|GM L99]] engine, a development of the [[GM LS engine#LS3|LS3]] with Active Fuel Management which allowed it to run on four cylinders during light load conditions.<ref>[http://paultan.org/archives/2008/07/23/2010-chevrolet-camaro-details-and-hi-res-photos/ 2010 Chevrolet Camaro Details and Hi-Res Photos]</ref>