Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
Chrysler/Jeep OBD1 Systems<br />
CHRYSLER/JEEP OBD1 SYSTEMS<br />
CHRYSLER/JEEP OBD1 SYSTEMS<br />
Chrysler Motors On-Board Computer Systems<br />
Chrysler Motors introduced its first electronic fuel injected vehicle in late<br />
1983. The on-board computer management systems used on Chrysler<br />
vehicles have evolved over the years, and their names have changed<br />
accordingly.<br />
1983-87: The on-board computer used in these vehicles is a splitsystem,<br />
composed of two separate units: the Logic Module and the<br />
Power Module. The Logic Module contains a microprocessor which<br />
processes data received from sensors located throughout the vehicle<br />
and makes decisions (based on these inputs) which effect engine<br />
operation. The Logic Module is usually located on the right-hand side,<br />
behind the kick panel. The Power Module supplies operating power to<br />
the Logic Module, and contains the circuits which control the highcurrent<br />
devices. Power Module operation is controlled by the Logic<br />
Module. The Power Module is located in the engine compartment, near<br />
the vehicle’s battery.<br />
1987-90: This system is called a Single Module Engine Controller<br />
(SMEC). This system still uses two separate circuit boards (Logic<br />
Module and Power Module). However, both circuit boards are located in<br />
a common enclosure.<br />
1989-95: This system is called a Single Board Engine Controller<br />
(SBEC). On this system, the Logic Module and Power Module circuit<br />
boards are integrated on a single circuit board.<br />
1993-97: Beginning in 1993, the computer was renamed the Powertrain<br />
Control Module (PCM). In addition to controlling the engine<br />
management system and emission system, the computer also takes an<br />
active role in controlling powertrain (transmission system) operation.<br />
Unless otherwise specified, all references to “computer” within<br />
this manual also apply to “Logic Module/ Power Module”,<br />
“SMEC”, “SBEC” or “PCM”.<br />
Jeep On-Board Computer Systems<br />
1993-95: In 1993, Jeep on-board computer systems (fuel injected<br />
vehicles only) were converted to the Chrysler on-board computer<br />
systems. All 1993 through 1995 fuel injected Jeep and Chrysler vehicles<br />
are equipped with similar on-board computer systems.<br />
68 CanOBD2&1