GM Sigma Vehicle Platform

The Sigma platform was a GM vehicle platform initially designed for executive cars but eventually expanded for a diverse range of luxury applications. It underpinned three distinct Cadillac models.

Names:	GM Sigma Platform, Sigma
Predecessor:	GM V Platform
Successor(s):	GM Alpha Platform, GM Omega Platform
Type:	Unibody
Supported Vehicle Type (s):	Luxury Sedan, Luxury Crossover, Luxury Station Wagon, Luxury Coupe
Layout:	Front-Engined Rear-Wheel Drive, Front-Engined All-Wheel Drive
Powertrain Type:	Gasoline
Debut:	2002 calendar year
On sale date:	2003 model year
Supported vehicles:	Cadillac CTS, Cadillac SRX, Cadillac STS, Cadillac SLS

Overview

As the first Cadillac-exclusive platform since the GM D-Body, the GM Sigma platform debuted in 2002 underneath the 2003 Cadillac CTS. Designed as a RWD platform, Sigma also accommodated all-wheel-drive (AWD) as well as an extended-wheelbase. The architecture featuring a four-wheel independent suspension setup with front control arms and a rear multi-link configuration.

Two iterations of the Sigma platform were released, with the second called Sigma II. The platform marked many firsts for the Cadillac luxury marque, including the first Cadillac manual transmission since the 1986 Cimarron, the first RWD luxury sedan with a Northstar engine, and the first non-limousine Cadillac sedan to be offered as an extended-wheelbase version (SLS).

2003 Cadillac CTS

2004 Cadillac SRX

2005 Cadillac STS

Cadillac SLS

With the introduction of the second-generation 2008 Cadillac CTS, General Motors launched the aforementioned Sigma II platform. Although the Sigma II shared the same 113.4 inch wheelbase as its predecessor, the reworked architecture was longer and wider, and remained exclusive to the Cadillac lineup despite sharing components with the Australian-designed GM Zeta platform.

At the end of its lifecycle, the CTS became the sole Cadillac to ride on the Sigma II platform, since the SRX was downsized (and moved to the Theta II platform) for 2010, the STS was discontinued after 2011, and the SLS was sunset in 2013.

2012 Cadillac CTS

2014 Cadillac CTS-V

Powertrain

GM Sigma Platform Production Vehicle Powertrain Specifications
Year	Vehicle	Transmission	Engine	Horsepower @ RPM	Torque @ RPM
2003 – 2004	Cadillac CTS	-	3.2L V6 LA3	220 @ 6000	220 @ 3400
2004 – 2007	Cadillac CTS	-	3.6L V6 LY7	255 @ 6200	252 @ 2800
2005 – 2007	Cadillac CTS	-	2.8L I4 LP1	210 @ 6500	194 @ 3300
2008 – 2010	Cadillac CTS	-	2.8L V6 LP1	210 @ 6800	182 @ 3600
2008 – 2009	Cadillac CTS	-	3.6L V6 LY7	263 @ 6200	253 @ 3100
2008 – 2011	Cadillac CTS	-	3.6L V6 LLT	304 @ 6400	273 @ 5200
2010 – 2011	Cadillac CTS	-	3.0L V6 LF1	270 @ 7000	223 @ 5700
2012 – 2013	Cadillac CTS	-	3.0L V6 LFW	270 @ 7000	223 @ 5700
2012 – 2014	Cadillac CTS Wagon and Coupe	-	3.6L V6 LFX	318 @ 6800	275 @ 4900
2014 – 2015	Cadillac CTS Sedan	-	3.6L V6 LFX	321 @ 6800	275 @ 4900
2004 – 2005	Cadillac CTS-V	Tremec Six-Speed Manual	5.7L V8 LS6	400 @ 6000	395 @ 4800
2006 – 2007	Cadillac CTS-V	Tremec Six-Speed Manual	6.0L V8 LS2	400 @ 6000	395 @ 4400
2009 – 2015	Cadillac CTS-V	Tremec Six-Speed Manual or GM Six-Speed Auto	6.2L V8 LSA	556 @ 6100	551 @ 3800
2004 – 2009	Cadillac SRX	-	3.6L V6 LY7	255 @ 6500	254 @ 2800
2004 – 2009	Cadillac SRX	-	4.6L V8 LH2	320 @ 6400	315 @ 4400
2005 – 2007	Cadillac STS	5-Speed Auto or 6-Speed Auto	3.6L V6 LY7	255 @ 6500	252 @ 3200
2008 – 2011	Cadillac STS	6-Speed Auto	3.6L V6 LLT	302 @ 6300	272 @ 5200
2005 – 2011	Cadillac STS	5-Speed Auto or 6-Speed Auto	4.6L V8 LH2	320 @ 6400	315 @ 4400
2006 – 2009	Cadillac STS-V	6-Speed Auto	4.4L V8 LC3	469 @ 6400	439 @ 3900
2007 – 2009	Cadillac SLS	6-Speed Auto	2.8L V6 LP1	209 @ 6500	194 @ 3300
2007 – 2009	Cadillac SLS	6-Speed Auto	3.6L V6 LY7	251 @ 6500	252 @ 3200
2007 – 2009	Cadillac SLS	6-Speed Auto	4.6L V8 LH2	320 @ 6400	315 @ 4400
2010 – 2011	Cadillac SLS	6-Speed Auto	3.6L V6 LLT	307 @ 6400	276 @ 5200
2011 – 2013	Cadillac SLS	6-Speed Auto	2.0L I4 LDK	259 @ 5300	266 @ 2000 – 5000
2011 – 2013	Cadillac SLS	6-Speed Auto	3.0L V6 LF1	268 @ 7000	221 @ 5600

Complete Table Coming Soon.

Vehicle Applications

GM Sigma Platform Production Vehicle Applications
Year	Vehicle
2003 – 2007	Cadillac CTS
2004 – 2007	Cadillac CTS-V
2004 – 2009	Cadillac SRX
2005 – 2011	Cadillac STS
2006 – 2009	Cadillac STS-V
2007 – 2013	Cadillac SLS
2008 – 2014	Cadillac CTS
2009 – 2015	Cadillac CTS-V

Production

Both iterations of the GM Sigma platform were manufactured at the GM Lansing Grand River plant in Michigan, GM Shanghai plant in China and the GM Kaliningrad plant in Russia.