Chrysler 300M 2002 Service Manual page 2811

GENERAL INFORMATION
Theory of operation: Four solenoids are used to
control the friction elements (clutches). The conti-
nuity of the solenoids circuits are periodically
tested. Each solenoid is turned on or off depending
on it's current state. An inductive spike should be
detected by the PCM during this test. If no spike is
detected, the circuit is tested again to verify the
failure. In addition to the periodic testing, the
solenoid circuits are tested if a gear ratio or pres-
sure switch error occurs. In this case, one failure
will result in the appropriate code being set.
Transmission Effects: The MIL will illuminate
and the transmission goes into neutral if code is set
above 35 Km/h (22 MPH), Limp-in mode when
vehicle speed is below 35 Km/h (22 MPH).
Possible causes:
> Open or shorted solenoid circuit(s) between PCM
and Transmission Solenoid/Pressure Switch as-
sembly
> Open ground circuit
> PCM connector problems
> Solenoid/Pressure Switch connector problem
> Solenoid/Pressure Switch assembly
> PCM
Name of code: P1776(47) - Solenoid Switch Valve
Latched in LR Position
When monitored: Continuously when doing par-
tial or full EMCC (PEMCC or FEMCC)
Set condition: If the transmission senses the LR
pressure switch closing while performing PEMCC
or FEMCC. This code will be set after two unsuc-
cessful attempts to perform PEMCC or FEMCC.
Theory of operation: The solenoid switch valve
(SSV) controls the direction of the transmission
fluid when the LR/TCC solenoid is energized. SSV
will be in the downshifted position in 1st gear, thus
directing the fluid to the LR clutch circuits. In 2nd,
3rd, and 4th, the SSV will be in the upshifted
position and directs the fluid into the torque con-
verter clutch (TCC).
When doing PEMCC or FEMCC, the LR pres-
sure switch should indicate no pressure if the SSV
is in the TCC position. If the LR pressure switch
indicates pressure while in PEMCC or FEMCC,
EMCC operation is aborted and inhibited to avoid
inadvertent application of the LR clutch. Partial
EMCC will be attempted if the LR pressure switch
does not indicate pressure. A second detection of
LR pressure results in setting the code.
Transmission Effects: At speeds above 72 Km/h
(45 MPH), EMCC is inhibited. Once speed falls
below 72 Km/h (45 MPH), the transmission will go
into Limp-in mode and the MIL will illuminate
after 5 minutes of substituted operation.
Possible causes:
> Valve body - Solenoid valve stuck in LR position
> Intermittent short to ground or open circuit in
LR Pressure Switch Sense circuit (with code 24
only)
> Solenoid Pressure Switch (with code P0841(24)
only)
> PCM (with code P0841(24) only)
Name of code: P0736(50) - Gear Ratio Error in
Reverse
P0731(51) - Gear Ratio Error in 1st
P0732(52) - Gear Ratio Error in 2nd
P0733(53) - Gear Ratio Error in 3rd
P0734(54) - Gear Ratio Error in 4th
P0715(56) - Input Speed Sensor Error
P0720(57) - Output Speed Sensor Error
P1794(58) - Speed Sensor Ground Error
When monitored: The transmission gear ratio is
monitored continuously while the transmission is
in gear.
Set condition: This code is set if the gear ratio is
not correct for a period of time.
– Codes 50 through 54 sets if the ratio of the
input RPM (Nt) to the output RPM (No) does
not match the given gear ratio.
– Code 56 sets if there is an excessive change in
input RPM in any gear
– Code 57 sets if there is an excessive change in
output RPM in any gear
– Code 58 sets after a PCM reset in neutral and
Nt/No equals a ratio of input to output of 2.50
A hard code sets within 3 seconds, an intermit-
tent code sets within 15 seconds.
Theory of operation: The transmission system
uses two speed sensors, one to measure input RPM
and one to measure output RPM. These inputs are
essential for proper transmission operation. There-
fore, the integrity of this data is verified through
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