Auto Shut Down (Asd) Relay-Pcm Output; Overdrive Indicator L A M P - P C M Output; Overdrive S O L E N O I D - P C M Output; Powertrain Control Module (Pcm) - Chrysler DODGE D150 1993 Service Manual

14 - 82 FUEL 'SYSTEM — . — ~ — — — «
INTAKE HEATER CYCLE CHART
I n t a k e
f e a t p e r a f w r e
Preheat Cycle Time
Ignition l£ey O N
Engine Not Running
Pestheat Cycle
Ignition Key O N
Snglne Running
Above 15 °C
(59 °F)
0 Seconds No
-8°C(18°F)to
15°C (59 °F)
10 Seconds
Yes
-17°C(1 °F)
-9 °C(]6°F)
15 Seconds Yes
«2d°C(-15°F)
to-18°C(0 °F)
17.5 Seconds Yes
Below-26 °C
(-15 *F)
20 Seconds Yes
J9114-239
AUTO SHUT DOWN (ASD) RELAY-PCM OUTPUT
The ASD relay is located in the engine compart­
ment (Fig. 14).
TORQUE CONVERTER
CLUTCH RELAY
A / C CLUTCH RELAY STARTER RELAY
AUTO SHUTDOWN RELAY
FUEL PUMP RELAY
DATA LINK
CONNECTOR
POWERTRAIN
CONTROL
MODULE J9314-164
Fig. 14 Relay Location—Typical
The ASD relay supplies battery voltage to the gen­
erator field winding to provide regulation of the
charging system. The ground circuit for the ASD re­
lay is controlled by the PCM. The PCM operates the
relay by switching the ground circuit on and off.
MALFUNCTION INDICATOR L A M P - P C M OUTPUT
The malfunction indicator lamp (formerly referred
to as the check engine lamp) illuminates at the bot­
tom of the instrument panel each time the ignition
key is turned on. It will stay on for three seconds as
a bulb test.
If the powertrain control module (PCM) receives an
incorrect signal, or no signal from certain sensors or
emission related systems, the lamp is turned on. This
is a warning t h a t the PCM has recorded a system or
sensor malfunction. In some cases, when a problem is
declared, the PCM will go into a limp-in mode. This
is an attempt to keep the system operating. It signals
an immediate need for service.
The lamp can also be used to display a diagnostic
trouble code (DTC). Cycle the ignition switch On-Off-
On-Off-On within three seconds and any codes stored
in the PCM memory will be displayed. This is done
in a series of flashes representing digits. Refer to On-
Board Diagnostics in the General Diagnosis section
of this group for more information.
OVERDRIVE INDICATOR L A M P - P C M OUTPUT
Indicates the state of the overdrive defeat switch
on the instrument panel.
OVERDRIVE S0LEN0ID-PCM OUTPUT
The overdrive solenoid is used on vehicles t h a t
have an automatic transmission. The solenoid is op­
erated by the PCM. It controls shifting in and out of
overdrive through the overdrive solenoid. Refer to
Group 21 for overdrive solenoid service.
SCI TRANSMIT—PCM OUTPUT
SCI Transmit is the serial data communication
transmit circuit for the DRB II scan tool. The PCM
transmits data to the DRB II through the SCI Trans­
mit circuit.
SPEED C0NTR0L-PCM OUTPUT
The speed control vacuum and vent solenoids are
operated by the PCM. The vacuum solenoid main­
tains vacuum at a required pressure to resume, set
or accelerate the speed control system. The vent so­
lenoid allows vacuum to bleed off during decelera­
tion, when the brakes are applied, or the
transmission is shifted into park or neutral.
TACHOMETER-PCM OUTPUT
This output generates the necessary signal needed
to operate a dealer installed tachometer (if equipped).
The input for this signal is from the engine speed
sensor.
WAIT-TO-START L A M P - P C M OUTPUT
The wait-to-start lamp is turned on and off by the
PCM based on the charge air temperature sensor in­
put.
The light is turned on when the ignition is first ac­
tivated. It will remain on for two seconds as a bulb
test. If the PCM reads intake manifold air tempera­
ture below 15°C (59°F), it will t u r n the wait-to-start
light on for the intake heater preheat cycle. The
light stays on until the preheat cycle is over.
The wait-to-start light will flash on and off if the
charge air temperature sensor input to the PCM is