Dodge 2004 Neon SX2 Diagnostic Manual page 732

Possible causes:
> Pressure switch sense circuit shorted to battery
between PCM and solenoid pack.
> Low line pressure
> Solenoid/Pressure Switch assembly
Name of code: P0944(35) - Loss Of Prime
When monitored: If the transmission is slipping
in any forward gear and the pressure switches are
not indicating pressure, a loss of prime test is run.
Set condition: If the transmission begins to slip in
any forward gear, and the pressure switch or
switches that should be closed for a given gear are
open, a loss of prime test begins. All available
elements (in 1st gear LR, 2/4 and OD, in 2nd, 3rd,
and 4th gear 2/4 and OD) are turned on by the
PCM to see if pump prime exists. The code is set if
none of the pressure switches respond. The PCM
will continue to run the loss of prime test until
pump pressure returns.
Theory of operation: The loss of prime test is
used to prevent transmission faults, which can be
caused by a lack of pump prime.
Transmission Effects: Vehicle will not move or
transmission slips. Normal operation will continue
if pump prime returns.
Possible causes:
> Low transmission fluid level
> PRNDL indicates a valid OD code in the hydrau-
lic reverse position
> Transmission fluid filter clogged or damaged
> Transmission fluid filter improperly installed
(Bolts loose or O-ring missing)
> Oil pump - If a customer has a problem when the
transmission is cold. Where someone shifts to
reverse, reverse is engaged, and then shifts to
OD and does not get OD (gets a neutral condi-
tion), and then can not get reverse or OD for 3-20
seconds, replace the oil pump. High side clear-
ance in the oil pump will set a code 35. The pump
will prime upon start-up, but as the torque
converter purges air (drain down) the air will
leak across the inner rotor into the pump suction
port and cause a loss of prime right after the
GENERAL INFORMATION
shift into OD. After 3 - 20 seconds, pump prime
will return and normal operation will continue.
The pump should be replaced only after all other
possible causes above have been checked and
verified.
Name of code: P1790(36) - Fault Immediately
After Shift
When monitored: After a gear ratio error is
stored.
Set condition: This code is set if the associated
gear ratio code is stored within 1.3 seconds after a
shift.
Theory of operation: This code will only be
stored along with a 50 series code. If this code is
set, it indicates the problem is mechanical in na-
ture. When this code exists, diagnosing the trans-
mission should be based on the associated gear
ratio code and primarily mechanical causes should
be considered.
Transmission Effects: None
Possible causes:
> Mechanical causes as listed under associated
gear ratio code.
Name of code: P1775(37) - Solenoid Switch Valve
Latched in TCC Position
When monitored: During an attempted shift into
1st gear.
Set condition: This code is set if three unsuccess-
ful attempts are made to get into 1st gear in one
given key start.
Theory of operation: The solenoid switch valve
(SSV) controls the direction of the transmission
fluid when the LR/TCC solenoid is energized. The
SSV will be in the downshifted position in 1st gear,
thus directing the fluid to the L-R clutch circuit. In
2nd, 3rd, and 4th, it will be in the upshifted
position and directs the fluid into the torque con-
verter clutch (TCC).
When shifting into 1st gear, a special hydraulic
sequence is performed to ensure SSV movement
into the downshifted position. The LR pressure
switch is monitored to confirm SSV movement. If
movement is not confirmed (the LR pressure
switch does not close), 2nd gear is substituted for
1st.
Transmission Effects: Transmission will have no
1st gear (2nd gear will be substituted), and no
EMCC operation and the MIL will illuminate after
5 minutes of substituted operation.
Possible causes:
> PRNDL indicates a valid OD code in the hydrau-
lic reverse position
> Valve body - Solenoid valve stuck in TCC posi-
tion
> High idle speed
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