Dodge 2004 Neon SX2 Diagnostic Manual page 729

GENERAL INFORMATION
Theory of operation: The PCM uses three pres-
sure switches to monitor the fluid pressure in the
LR, 2/4, and OD clutch circuits. The pressure
switches are continuously monitored for the correct
states in each gear as shown below.
Transmission Effects: Normal operation will be
experienced if no other codes are present. Trans-
mission Control System will ignore the code.
Limp-in condition will only occur if code P0871(21)
is present with a code P0706(28).
Possible causes:
> If code P0944(35) is present, ignore code
P0871(21) and perform code P0944 diagnostic
procedures
> OD pressure switch sense circuit open or
shorted to ground between PCM and solenoid
pack
> OD pressure switch sense circuit shorted to
battery
> Solenoid/Pressure Switch assembly
> Loose valve body bolts
> Plugged filter - internal transmission or
torque converter failure
> PCM
Name of code: P0846(22) - 2/4 Pressure Switch
Sense Circuit
When monitored: Whenever the engine is run-
ning.
Set condition: This code is set if the 2/4 pressure
switch is open or closed at the wrong time in a
given gear.
Theory of operation: The Transmission system
uses three pressure switches to monitor the fluid
pressure in the LR, 2/4, and OD elements. The
pressure switches are continuously monitored for
the correct states in each gear as shown below.
Transmission Effects: If the 2/4 pressure switch
is identified as closed in P or N, the code will
immediately be set and normal operation will be
allowed for that given key start. If the problem is
identified for 3 successive key starts, the transmis-
sion will go into Limp-in mode.
If the 2/4 pressure switch is identified as being
closed in 1st or 3rd gear and was not identified as
being closed in P or N, then 2nd gear or 4th gear
will be substituted for 1st or 3rd gear depending on
throttle angle and vehicle speed. A short period of
time after the gear substitution, the transmission
will return to normal operating mode. If the trans-
mission is shifted back into 1st or 3rd gear through
normal operation, and the 2/4 pressure switch
remains closed, 2nd or 4th gear will be substituted
briefly and then resume normal operation. If four
gear substitutions occur in a given key start, the
transmission will go into Limp-in mode.
If the 2/4 pressure switch is open (indicating no
2/4 clutch pressure) in 2nd or 4th gear, the Trans-
mission Control System sets code P0846(22) and
continues with normal operation. The transmis-
sion will only go into Limp-in mode if a code
P0706(28) is also present. If no 2/4 clutch pressure
is present a gear ratio code P0732(52) or P0734(54)
will be set and cause the limp-in condition.
Possible causes:
> If code P0944(35) is present, ignore code
P0846(22) and perform code P0944 diagnostic
procedures
> 2/4 pressure switch sense circuit open or
shorted to ground between PCM and solenoid
pack
> 2/4 pressure switch sense circuit shorted to
battery
> Solenoid/Pressure Switch assembly
> Transmission overheated - Excessive regula-
tor valve leakage in valve body causing high
line pressure which results in 2/4 solenoid
blow-off in 1st or 3rd gear. May require new
valve body if it happens only when hot.
> Loose valve body bolts
> Plugged filter - internal transmission or
torque converter failure
> PCM
Name of code: P0841(24) - LR Pressure Switch
Sense Circuit
When monitored: Whenever the engine is run-
ning.
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