Removal; Installation; Powertrain Control Module Description Operation - Sensor Return - Pcm Input; Operation - Data Bus Communication Receive - Pcm Input - Chrysler PT Cruiser Service & Repair Manual

PT
HEATED SEAT MODULE (Continued)

REMOVAL

WARNING: THERE ARE MANY SHARP METAL
EDGES ON THE SEAT CUSHION FRAME AND SEAT
ADJUSTER RAILS UNDER THE SEAT. WHEN PER-
FORMING THIS SERVICE, A LONG-SLEEVED SHIRT
AND GLOVES SHOULD BE WORN IN ORDER TO
AVOID UNNECESSARY CUTS AND ABRASIONS TO
EXPOSED SKIN.
(1) Move the passenger power seat to its full up
and full rear stop positions.
(2) Disconnect and isolate the battery negative
cable.
(3) Working under the seat, release the two plastic
push-in fasteners from either the module or the
mounting holes in the power seat cushion pan (Fig.
6).
Fig. 6 Heated Seat Module Location- Typical
1 - SEAT CUSHION FRAME
2 - HEATED SEAT MODULE
3 - WIRE HARNESS CONNECTOR
4 - POWER SEAT TRACK FRONT BRACKET
(4) Disconnect the power seat wire harness connec-
tor from the heated seat module connector receptacle.
(5) Remove the heated seat module from the power
seat track.

INSTALLATION

(1) If the two plastic push-in fasteners for the
heated seat module were damaged during removal,
install new fasteners onto the heated seat module.
(2) Reconnect the power seat wire harness connec-
tor to the heated seat module connector receptacle.
Be certain that the cavities in the power seat wire
ELECTRONIC CONTROL MODULES
harness connector are aligned with the terminals in
the heated seat module connector receptacle before
pushing the connector firmly into place.
(3) Install the heated seat module on the power
seat cushion pan.
(4) Reconnect the battery negative cable.
POWERTRAIN CONTROL
MODULE
DESCRIPTION
OPERATION - SENSOR RETURN - PCM INPUT
The sensor return circuit provides a low electrical
noise ground reference for all of the systems sensors.
The sensor return circuit connects to internal ground
circuits within the Powertrain Control Module
(PCM).
OPERATION - DATA BUS COMMUNICATION
RECEIVE - PCM INPUT
The PCM uses the SCI communication bus to pre-
form engine diagnostics and flash operations. The
transmission side of the PCM uses the SCI commu-
nication bus to flash new software. However, diagnos-
tics is performed via the vehicles J1850 bus for the
transmission side of the PCM.

OPERATION - IGNITION SENSE - PCM INPUT

The ignition sense input informs the Powertrain
Control Module (PCM) that the ignition switch is in
the crank or run position.

OPERATION - PCM GROUND

Ground is provided through multiple pins of the
PCM connector. Depending on the vehicle there may
be as many as two different ground pins. There are
power grounds and sensor grounds.
The power grounds are used to control the ground
side relays, solenoids, ignition coil or injectors. The
signal ground is used for any input that uses sensor
return for ground, and the ground side of any inter-
nal processing component.
The PCM case is shielded to prevent RFI and EMI.
The PCM case is grounded and must be firmly
attached to a good, clean body ground.
Internally all grounds are connected together, how-
ever there is noise suppression on the sensor ground.
For EMI and RFI protection the housing and cover
are also grounded separately from the ground pins.
8E - 5