ACtion Magazine - NAPA - Spring 2016 - (Page 22)

A new Jeep, a new liquid line and more By Paul Weissler, MACS Senior Technical Correspondent Paul Weissler There's a new Jeep on the market named Renegade. It's even smaller than a Wrangler, and is the first one made outside the United States. Although the engineering was largely done here, including the all-wheel-drive and four-wheel-drive systems, the new Renegade is being made in Italy, at the factory of the parent Fiat Chrysler Automobiles (FCA). The Renegade is sharing its basic platform with a new Fiat, the 500X (not to be confused with the 500 or 500L). The likely most popular engine choice will be the Chrysler 2.4-liter Tiger Shark, but Renegade is being made in Italy along with the corporate 1.4-liter turbocharged engine. Both of these engines (along with a 2.0-liter four) are used in the Dodge Dart. What is most technically novel about both the Renegade and upcoming 500X is the A/C liquid line: it's black plastic, the first non-metallic one we've ever seen. Also noteworthy is that the line includes the high-side service valve, which sits on a riser at the right front of the powertrain compartment (Figure 1). These new models also have a new electronic architecture called Atlantis. It's an upgrade from the PowerNet introduced in 2011 and is being used on most U.S. Figure 1: Black plastic liquid line debuts on new Jeep Renegade (and forthcoming Fiat 500X). Riser holds the high side service valve in this first Fiat Chrysler product line with this material application. 22 ACTION/NAPA * Spring 2016 built models. But as things are right now, Atlantis will be used alongside it, and will not replace it. Somewhat like the PowerNet, but with a different configuration. Atlantis (Figure 2) has two high-speed CAN (Controller Area Network) data busses; 500 kbps and one medium-speed (125 kbps) bus. We think it's worth talking about for two reasons: 1) Chrysler is describing it as a next generation architecture, which means that when it comes out with an all-new vehicle, that model will have Atlantis. 2) It has significant diagnostic attributes, different from PowerNet. Atlantis has the body computer (BCM) as its central brain and interconnection (gateway) between the three data busses. The BCM is under the dash to the left of the steering wheel, and includes the fuse box (Figure 9). It is just above the OBD-II plug. In addition to its gateway function, it holds vehicle configuration data plus lighting, locking and anti-theft. By comparison, PowerNet has just one high-speed and two medium-speed CAN busses. It uses the body computer as the gateway only for the high-speed CAN and the medium-speed interior CAN bus. The radio module contains the gateway for information exchange between the telematics bus and the interior bus. The Atlantis C-1 CAN is primarily powertrain and is connected to the OBD-II plug with 120-ohm termination resistors in the PCM and BCM. As you can see in Figure 3, the ABS and ORC (occupant restraint control) modules are on this bus, but primarily for data exchange communication, as they work primarily on C-2, the chassis and safety systems CAN bus. CAN-2 also has 120-ohm resistors at each end, one at the ABS, the other at the ORC. CAN-IHS (interior high speed) is the medium-high speed bus that covers comfort and entertainment systems. It includes the HVAC module, which is also connected to CAN-1 so it can communicate with the BCM and be controlled by the PCM. And no surprise, CANIHS also has 120-ohm termination resistors in the BCM and the IPC (instrument panel cluster module). Each bus, as measured at the OBD-II plug, should produce a 60-ohm reading with the power off and the bus connection intact. The OBD-II plug is a good place to start checking a data bus problem. Because of the way they're connected in a daisy chain, the Chrysler-recommended places for A/C circuit diagnosis are the HVAC, ETM (entertainment/telematics module) or RRM (radio receiver module, part of an option package or high trim level; not on all cars). At this point Chrysler's microPOD-II is the only communications interface between the OBD-II plug and the

Table of Contents for the Digital Edition of ACtion Magazine - NAPA - Spring 2016

ACtion Magazine - NAPA - Spring 2016
Watching yf
A/C Diagnostics and Troubleshooting
Staying visible in times of change
The compressor is not just a component
Restricted air flow
Externally Controlled variable displacement
A new Jeep
Increasing Facebook interactions
Mission possible
R-1234yf and other trends

ACtion Magazine - NAPA - Spring 2016