Dodge Neon / Neon SRT-4. Manual — part 623

The Transmission Control System may report any of the following DTC’s.
DTC

P-Code

Name of Code

Limp-in MIL

78

P1652

Serial communication link malfunction

No

No

-2

79

P0562

Low battery voltage

Yes

Yes

94

P0613

Internal TCM

Yes

Yes

Notes:
P1xxx DTC’s will set the MIL only after 10 seconds of vehicle operation.
1 - The MIL will be lit only if DTC P0706 is also present
2 - The MIL will be lit by the engine controller
3 - The MIL will be lit only if the engine controller is not calibrated for throttle substitution.
Yes (underlined) indicates that this DTC can take up to five minutes of problem identification before
illuminating the MIL.

3.3.8

DTC DESCRIPTIONS

Name of code: P0613(11, 13, 45, 94) - Internal
TCM
When monitored: Whenever the key is in the Run
or Run/Start position.
Set condition: This code is set whenever Trans-
mission Control System senses an internal error.
Theory of operation: The PCM is constantly
monitoring its internal processor. If an internal
problem is detected, this DTC will be set. This DTC
can also be set by a bad ground to the PCM and/or
Trans Control Relay.
Transmission Effects: The MIL will illuminate
(this DTC can take up to five minutes of problem
identification before illuminating the MIL) and the
transmission system will default to the Immediate
Shutdown routine.
Possible causes:

> PCM ground circuit.

> Relay ground circuit

> PCM

Name of code: P1684(12) - Battery was Discon-
nected (Informational code Only)
When monitored: Whenever the key is in the
Run/Start position.
Set condition: This code is set whenever the PCM
is disconnected from battery power (B+) or ground.
It will also be set during the DRBIII

t Battery

Disconnect procedure.
Theory of operation: A battery backed RAM
(Random Access Memory) is used to maintain some
learned values. When the battery B(+) is discon-
nected, the memory is lost. When the B(+) is
restored, this memory loss is detected by the PCM.
The code is set and the learned values are initial-
ized to known constants or previously learned
values from EEPROM (Electronic Erasable Pro-
grammable Read Only Memory). This results in
the reinitialization of some parameters.
Transmission Effects: Loss of trouble code data.
Immediate Limp-in mode if power is lost while

operating the vehicle. Normal operation is re-
sumed if the power is restored during the same key
start.
Possible causes:

> Battery voltage removed from PCM

> PCM disconnected

> Dead Battery

> Low battery voltage during cranking

> Battery Disconnect by DRBIII

t or MDS2

> PCM ground circuit missing.

Name of code: P0891(14) - Transmission Relay
Always On
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
greater than 3 volts at the Trans Relay Output
(switched battery) terminal of the PCM 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.
Transmission Effects: The MIL will illuminate
and the transmission system defaults to Logical
Limp-in mode. Logical Limp-in mode results in the
same modes of operation as Limp-in. Since the
relay is stuck “on”, the PCM can not open the relay,
and the PCM shifts to 2nd gear.
Possible causes:

> Relay failure (welded contacts)

> Short to battery in 12-volt supply and/or

Transmission Control Relay Output circuit(s)

> Short to voltage

> PCM connector problems

> PCM

6

GENERAL INFORMATION

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

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.

7

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.

8

GENERAL INFORMATION

Set condition: This code is set if the LR pressure
switch is either 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.

Transmission Effects: If a set condition is iden-
tified, 1st gear and torque converter lock-up
(EMCC) will be inhibited. The vehicle will launch
in 2nd gear and shift normally through the gears
without allowing EMCC. If during the same key
start, the set condition is no longer valid, the
transmission will return to normal operation (1st
and EMCC available). Limp-in will not occur un-
less code P0841(24) is accompanied by a code
P0706(28) and the MIL will illuminate after 5
minutes of substituted operation.
Possible causes:

> If code P0944(35) is present, ignore code

P0841(24) and perform code P0944(35) diag-
nostic procedures

> LR pressure switch sense circuit, open or

shorted to ground between PCM and solenoid
pack

> LR pressure switch sense circuit shorted to

battery

> Solenoid/Pressure Switch assembly

> Valve body - solenoid switch valve stuck in

LU position. May be accompanied by a code
P1775(37)

> Loose valve body bolts

> Plugged filter - internal transmission or

torque converter failure

> PCM

Name of code: P0706(28) - Check Shifter Signal
When monitored: Continuously with the key on.
Set condition: 3 occurrences in one key start of an
invalid PRNDL code which lasts for more than 0.1
second.
Theory of operation: The C1 through C4 (T1, T3,
T41, and T42) sense circuits communicate the shift

lever position to the PCM. Each circuit is termi-
nated at the transmission with a switch. Each
switch can be either open or closed, depending on
the shift lever position. The PCM can decode this
information and determine the shift lever position.
Each shift lever position has a certain combination
of switches which will be open and closed, this is
called a PRNDL code. There are 4 switches, there-
fore: there are many possible combinations of open
and closed switches (codes). However, there are
only 9 valid codes (8 for AutoStick), one for each
gear position and three recognized between gear
codes. The remainder of the codes should never
occur, these are called invalid codes. The following
chart shows the normal switch states for each shift
lever position.

The following are DRBIII

t reported Shift Le-

ver Error codes (chart)

Transmission Effects and possible causes:
Scenario 1) - All PRNDL lights stay illuminated
indefinitely in Park following a Key start.

> Wrong Part Number PCM for application

> TRS connector not plugged in

> C1 through C4 (T1, T3, T41, or T42) circuits are

open, shorted to ground, or shorted to 12 volts.

> PCI bus failure (Open or shorted resulting in no

communication to BCM or Cluster)

> TRS

> PCM

> BCM
Scenario 2) - “P” is indicated following a key start
but all PRNDL lights illuminate in “N” following a
shift from “R” to “N”. If PRNDL lights illuminate in
“N” and shifter is moved directly into “3” or “L”

9

GENERAL INFORMATION