Dodge 2004 Neon SX2 Diagnostic Manual page 728

Name of code: P0888(15) - Relay Output Always
Off
When monitored: Continuously
Set condition: This code is set when less than 3
volts are present at the Transmission Control Re-
lay Output (switched battery) terminals at the
PCM, when the PCM is energizing the relay.
Theory of operation: The transmission control
relay is used to supply power to the solenoid pack
when the transmission is in normal operating
mode. When the relay is off, no power is supplied to
the solenoid pack and the transmission is in
Limp-in mode. The relay output is fed back to the
PCM. It is referred to as the Transmission Control
Relay Output circuit or switched battery.
After a controller reset (ignition key turned to
the run position or after cranking engine), the
controller energizes the relay. Prior to this the
PCM verifies that the contacts are open by check-
ing for no voltage at the switched battery termi-
nals. After the relay is energized, the PCM moni-
tors the terminals to verify that the voltage is
greater than 3 volts.
Transmission Effects: The MIL illuminates and
the transmission system defaults to Limp-in mode.
Possible causes:
> Relay failure (intermittent relay function
caused by oxidized or contaminated relay
contacts)
> Short to ground or open circuit in the Trans-
mission Control Relay circuit(s)
> PCM connector problem
> PCM
Name of code: P0725(18) - Engine Speed Sensor
Circuit
NOTE: This code is not a Transmission Input
Speed Sensor DTC
When monitored: Whenever the engine is run-
ning.
Set condition: This code is set when the engine
speed sensed by the PCM is less than 390 RPM or
greater than 8000 RPM for more than 2.0 seconds.
Theory of operation: The PCM uses a new dual
port RAM internal to the controller to send the
Crank Sensor signal to the Transmission Control
System. If the PCM interprets this signal to be out
of range when the engine is running the code is set.
Transmission Effects: The MIL illuminates and
the transmission system defaults to Limp-in mode.
Possible causes:
> Engine DTC (engine rpm related) present
> PCM
Name of code: P1694(19) - Bus Communication
with Engine Module
GENERAL INFORMATION
When monitored: Continuously with key on.
Set condition: If no PCI bus messages are re-
ceived from the Powertrain Control Module (PCM)
for 10 seconds.
Theory of operation: The PCM uses a new dual
port RAM internal to the controller to communi-
cate with the Transmission Control System. The
Transmission Control System relies on certain en-
gine information to function properly. The Trans-
mission Control System continuously monitors the
internal engine bus to check for messages broad-
cast from the PCM.
Transmission Effects: Delayed 3-4 shifts. No
EMCC and early 3-4 shifts for a few minutes after
engine is started.
Possible causes:
> PCM
Name of code: P0890(20) - Switched Battery
When monitored: Ignition key is turned from off
position to run position and/or ignition key is
turned from crank position to run position.
Set condition: This code is set if the PCM senses
voltage on any of the pressure switch inputs prior
to the PCM energizing the relay.
Theory of operation: The transmission control
relay is used to supply power to the solenoid pack
when the transmission is in normal operating
mode. When the relay is off, no power is supplied to
the solenoid pack and the transmission is in
Limp-in mode. The relay output is fed back to the
PCM. It is referred to as the Transmission Control
Relay Output circuit or switched battery.
Immediately after a controller reset (ignition key
turned to the run position or after cranking en-
gine), the PCM verifies that the relay contacts are
open by checking for no voltage at the switched
battery terminals. After this is verified, the voltage
at the pressure switches is checked. There should
be no voltage on the pressure switches at this time.
The PCM will then activate the relay.
Transmission Effects: The MIL illuminates and
the transmission system defaults to Limp-in mode.
Possible causes:
> Short to battery on one or more pressure
switch sense circuits
> PCM connector problems
> PCM
Name of code: P0871(21) - OD Pressure Switch
Sense Circuit
When monitored: Whenever the engine is run-
ning.
Set condition: This code is set if the OD pressure
switch is open or closed at the wrong time in a
given gear.
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