2006 MERCEDES-BENZ SPRINTER sensor

The NAG1 will default in the current gear position
if a DTC is detected, then after a key cycle or shift
to park the transmission will go into Limp-in, which
is mechanical 2nd gear. Some DTC's may allow the
transmission to resume normal operation (recover)
if the detected problem goes away. Permanent
limp-in DTC will recover when the key is cycled, but
if the same DTC is detected for three key cycles the
system will not recover and the DTC must be
cleared from the TCM with the DRBIII scan tool.
Once the DRBIIItis in the Transmission portion
of the diagnostic program, it constantly monitors
the TCM to see if the system is in limp-in mode. If
the transmission is in limp-in mode, the DRBIIIt
will flash the red LED.
3.2.1 CONTROLLER MODES OF
OPERATION
Permanent limp-in mode
When the TCM determines there is a non-
recoverable condition present that will not allow
proper transmission operation, it will place the
transmission in permanent limp-in mode. When the
condition occurs the TCM will turn off all solenoids
as well as the solenoid supply output circuit. If this
occurs while the vehicle is moving, the transmission
will remain in the current gear until the ignition is
turned off or shifter is placed in the9P9position.
Once the shifter has been placed in9P9the Trans-
mission will only allow 2nd gear operation. If the
problem occurs while the vehicle is not moving the
transmission will only allow 2nd gear operation.
Temporary limp-in mode
This mode is the same as the permanent limp-in
mode except if the condition is no longer present the
system will resume normal operation. (Recoverable
DTC)
Undervoltage limp-in mode
When the TCM detects that system voltage has
dropped below 8.5 volts it will disable voltage de-
pendant diagnostics and place the transmission in
the temporary limp-in mode. When the TCM senses
that the voltage has risen above 9.0 volts, normal
transmission operation will be resumed.
Hardware Error Mode
When the TCM detects a major internal error the
transmission will be placed in the permanent
limp-in mode and cease all communication over the
CAN bus. Once the TCM has entered this mode
normal transmission operation will not resume un-
til all DTC's are cleared from the TCM.
Loss of Drive
If the TCM detects a situation that has resulted or
may result in engine or transmission failure, the
transmission will be placed in the neutral position.Improper Ratio, Input Sensor Overspeed, or Engine
Overspeed DTC's will cause the loss of drive.
Controlled Limp-in Mode
When a failure condition does not require the TCM
to shut down the solenoid supply, but the failure is
of a degree where the TCM will place the transmis-
sion into a predefined gear, there will be several
shift performance issues. Examples of this are, with
the transmission slipping the controller will at-
tempt to place the transmission into third gear and
maintain third gear for all forward drive conditions.
Another example is some of the CAN bus message
issues if the TCM does not receive required infor-
mation from the Engine Controller, then default
values are used which may result in poor transmis-
sion shift performance.
3.2.2 MIL ILLUMINATION
For failures detected by the Transmission Con-
troller that result in the controller placing the
transmission into a limp-in mode, except for System
Overvoltage and System Undervoltage DTCs, the
MIL will be illuminated. The Transmission Control
Module will inform the ECM over the CAN bus that
a failure has occurred. The ECM will illuminate the
MIL. If the condition is removed and the failure
becomes Stored (Intermittent), the Transmission
controller will stop reporting that the DTC is active
and the ECM will extinguish the MIL.
NOTE: The MIL will light when the problem is
first detected and it will not go off until the
next ignition cycle, after all problem
conditions have been checked for their
presence. This normally takes several
minutes of driving.
3.2.3 SOLENOIDS
1-2/4-5 solenoid -The 1-2/4-5 solenoid is activated
when the TCM determines that the transmission
must shift into or out of 2nd gear or 5th gear. The
solenoid is only activated during the shifting of the
transmission. When the solenoid is activated, hy-
draulic pressure is applied to the proper shift ele-
ments in the transmission to allow the desired shift.
Once the shift is completed, the solenoid is turned
off.
2-3 solenoid -The 2-3 solenoid is activated when
the TCM determines that the transmission must
shift into or out of 3rd gear. The solenoid is only
activated during the shifting of the transmission.
When the solenoid is activated hydraulic pressure
is applied to the proper shift elements in the trans-
mission to allow the desired shift. Once the shift is
completed, the solenoid is turned off.
2
GENERAL INFORMATION

3-4 solenoid -The 3-4 solenoid is activated when
the TCM determines that the transmission must
shift into or out of 4th gear. The solenoid is only
activated during the shifting of the transmission.
When the solenoid is activated, hydraulic pressure
is applied to the proper shift elements in the trans-
mission to allow the desired shift. Once the shift is
completed, the solenoid is turned off.
TCC solenoid -The TCC solenoid is activated
when the TCM determines that the Torque con-
verter clutch should be activated. The TCC clutch is
a variable slip torque clutch that allows control of
torque converter slip from 5% to 95.5% of full TCC
engagement. The clutch is controlled by the TCC
solenoid which is pulse width modulated (PWM) to
provide the desired amount of slip.
Shift Pressure Solenoid -The Shift Pressure
Solenoid is activated when the TCM determines
that a transmission shift is required. The solenoid
is PWM controller to allow the proper amount of
hydraulic pressure to the shift elements. The sole-
noid is only activated during the shifting of the
transmission. When the solenoid is activated, hy-
draulic pressure is removed from the proper shift
elements to allow the desired shift. Once the shift is
completed, the solenoid is turned off.
Modulation pressure solenoid -The modulation
pressure is always active. The solenoid is pulse
width modulated (PWM) controlled and is used to
modulate the hydraulic system pressure to the
desired pressure.
3.2.4 TRANSMISSION COMPONENT
DESCRIPTIONS
Shift Assembly
The Shift Lever Selector transmits all selector lever
positions, as well as selected shift ranges to the
TCM over the CAN Bus. At the same time, the
selector lever positions P, R, N, and D are transmit-
ted by a cable to the selector lever shaft in the
transmission.
Brake shift inter-lock
To prevent unauthorized shifting out of the park
position, the Selector lever is locked in the Park
position until the ignition key is turned to the run
position and the brake pedal is pressed. This will
allow the driver to shift out of the park position.
Reverse Lamp Output
The Reverse Light Switch is integrated into the
shifter module and controls the reverse lights.
Reverse Inhibitor
The Shift Lever Assembly constantly monitors ABS
wheel speed to prevents an inadvertent selection of
reverse at speeds above approximately 6.4 Km/h(4MPH). The Reverse inhibitor is part of the Shift
Lever Assembly and is controlled by the Shift Lever
Assembly module.
Trans temp sensor - P/N Switch circuit
The TCM will detect the selector lever in park and
neutral positions. The TCM does this by monitoring
the Transmission temperature sensor signal along
with the shifter position signals. The P/N switch
contact is operated by a cam located in the trans-
mission which, opens a reed contact switch that is
wired in series with the transmission temperature
sensor. When the P/N contact switch is opened in
park and neutral, the TCM senses a high transmis-
sion temperature. Confirming the P/N switch sta-
tus. Note: In park or neutral, the TCM uses engine
temperature (to avoid setting a DTC). The TCM
sends a hardwired signal to the ECM that will allow
the ECM controlled start circuit to engage in P or N
only. The TCM also sends a P/N bus message to the
ECM to confirm the P/N switch status.
The Normal Transmission Temperature Sensor
resistance is between 500.0 and 2500.0 ohms.
The normal voltage limits for the transmis-
sion temperature sensor, are between 0.5 and
3.0 volts.
Input Speed Sensors
The NAG1 transmission has two input speed sen-
sors N2 and N3, both speed sensors are located on
the valve body and report DTC's for the input speed
sensors errors. The speed sensors are Hall Effect
speed sensors that are used by the TCM to calculate
the transmissions input speed. Since the input
speed could not be measured directly, two of the
drive elements are measured. Two input speed
sensors were required because both drive elements
are not active in all gears. The input sensors N2 and
N3 will report the same input speed in gears 2nd,
3rd or 4th. If the N2 and N3 input speed signals are
not the same in these gears then there is an issue
with the transmission and the DTC Input Sensors
Mismatch will be set.
The N3 input speed is not reported in1st and 5th
gears. The N2 sensor is not reported in Reverse.
The Input Speed Sensor Overspeed is a rationality
check that is intended to indicate a major transmis-
sion failure and will cause a loss of drive (place the
transmission in Neutral)
Output Speed Sensor (ABS signal)
The NAG1 transmission does not have an output
shaft speed sensor. The TCM uses the ABS (An-
tilock Brake System) Wheel Speed sensor informa-
tion, it receives over the CAN bus, to calculate the
transmissions output shaft speed. The TCM moni-
tors the ABS system for functionality and reports
ABS speed sensor and communication DTCs, which
will affect proper transmission operation.
3
GENERAL INFORMATION

3.2.5 TRANSMISSION OPERATION AND
SHIFT SCHEDULING
The transmission covered in this manual has
unique shift schedules depending on the tempera-
ture of the transmission oil. The transmission oil
temperature has a decisive effect on the shift qual-
ity of the transmission. The shift schedule is modi-
fied to extend the life of the transmission while
operating under extreme conditions and to improve
driver comfort by modifying shift schedules.
The transmission oil temperature is measured
with a Temperature Sensor on the NAG1 transmis-
sion. The Temperature Sensor is an integral com-
ponent of the Transmission Solenoid assembly. If
the Temperature Sensor is causing a problem, a
DTC will be set in the TCM.
The Transmission Temperature Sensor is wired in
series with the Park /Neutral (P/N) switch. The P/N
switch is also located in the transmission. The trans-
mission temperature is only read by the TCM when
the P/N switch closes while in the R, D position.
When the shifter lever is in the park or neutral
position, the P/N switch opens and the temperature
being displayed is Engine temperature.
AutoStick Feature (If equipped)
This feature allows the driver to manually shift the
transaxle when the shift lever is moved sideways to
the (+ / -) in position D to adjust the shift range.
3.2.6 TRANSMISSION ADAPTIVES -
INITIALIZE AND STORE
Initialize Adaptive -This TCM function should be
used when a new transmission has been placed in
the vehicle. This command will reset the TCM
adaptive to the factory setting.
Store Adaptive -This command should be used
after the vehicle has been test driven by the tech-
nician to store any learned adaptive changes that
occurred during the test drive. During normal op-
eration adaptive are updated every 10 minutes.
Using this command the latest adaptive will be
written to the TCM immediately.
3.3 DIAGNOSTIC TROUBLE CODES
Diagnostic trouble codes (DTC's) are codes stored
by the Transmission Control Module (TCM) and the
Shift Lever Assembly Module (SLA) to help diag-
nose Transmission and Shifter problems. They are
viewed using the DRBIIItscan tool.
Always begin by performing a visual inspection of
the wiring, connectors, cooler lines and the trans-
mission. Any obvious wiring problems or leaks
should be repaired prior to performing any diagnos-
tic test procedures. Some engine driveability prob-lems can be misinterpreted as a transmission prob-
lem. Ensure that the engine is running properly
and that no ECM DTC's are present that could
cause a transmission complaint.
If there is a communication K-ABS,Shifter or
K-TCM circuit problem, trouble codes will not be
accessible until the problem is fixed. The DRBIIIt
will display an appropriate message. The following
is a possible list of causes for a bus problem:
± open or short to ground/battery in K line
circuit.
± internal failure of any module or component
connected to the K line circuit
Each diagnostic trouble code is diagnosed by
following a specific testing sequence. The diagnostic
test procedures contain step-by-step instructions
for determining the cause of a transmission diag-
nostic trouble code. Possible sources of the code are
checked and eliminated one by one. It is not neces-
sary to perform all of the tests in this book to
diagnose an individual code. These tests are based
on the problem being present at the time that the
test is run.
If the TCM records a DTC that will adversely
affect the vehicles transmission, it will request (via
the communication bus) that the ECM illuminate
the Malfunction Indicator Lamp (MIL). All trans-
mission DTC's will be stored in the TCM.
3.3.1 ACTIVE (HARD) CODE
Any Diagnostic Trouble Code (DTC) that is set
whenever the system or component is monitored is
an Active code. This means that the problem is
there every time the TCM checks that system or
component. Some codes will set immediately at
start up and others will require a road test under
specific conditions to set the DTC. It must be
determined if a code is Active (repeatable) or Stored
(Intermittent) before attempting diagnosis.
3.3.2 STORED (INTERMITTENT) CODE
A diagnostic trouble code that is not there every
time the TCM checks the circuit or function is a
Stored (Intermittent) code. Problems that come and
go like this are the most difficult to diagnose, they
must be looked for under the specific conditions
that cause them. If the DTC is reset (after an
ignition cycle) the DTC will be set to Stored (Inter-
mittent) status. A DTC status can be9Active9or
9Stored9(Intermittent). Active is when the DTC is
present in the controller and the transmission is in
the particular mode of operation for that DTC.
Stored means that the DTC occurred at some point,
but is not currently present, or the conditions have
not been right to check for the presence of the
problem, when a DTC is classified as Stored (Inter-
mittent), no TCM reaction is required.
4
GENERAL INFORMATION

5.0 REQUIRED TOOLS AND
EQUIPMENT
> DRBIIIt(diagnostic read-out box) - DRBIIIt
must use the latest release level.
> Jumper wires
> Test Light
> Ohmmeter
> Voltmeter
6.0 GLOSSARY OF TERMS
6.1 ACRONYMS
ABSAntilock Braking system
A/CAir conditioner
A/DAnalog to Digital conversion
APPAccelerator Pedal Position
CANController Area Network (Vehicle
Bus System)
CKTCircuit
DLCData Link Connector
DRBIIItDiagnostic Readout Box
DTCDiagnostic Trouble Code
ECMDiesel Engine Controller
EMCCElectronically Modulated Converter
Clutch
IODIgnition off-draw
ISSInput Speed Sensor (N2 and N3)
KK line communication bus
LEDLight Emitting Diode
MILMalfunction Indicator LampOSSOutput Speed Sensor (derived from
the ABS controller)
PEMCCPartial Electronically Modulated
Converter Clutch
PWMPulse width modulated
SKREEMSentry Key Remote Entry Module
SLAShift Lever Assembly
SWSwitch
TCCTorque Converter Clutch
TCMTransmission Control Module
TPThrottle Position
TRDTorque Reduction
TTSTransmission Temperature Sensor
1-2/4-5
solenoidcontrols the shift into and out of
2nd gear or 5th gear.
V2-3 so-
lenoidcontrols the shift into and out of 3rd
gear
V3-4 so-
lenoidcontrols the shift into and out of 4th
gear
VTCC
solenoidis pulse width modulated and con-
trols the TCC clutch
Shift
Pressure
Solenoidis a pulse width modulated solenoid
and controls the hydraulic pressure
to the shift elements.
Modula-
tion
pressure
solenoidis a pulse width modulated solenoid
and controls the hydraulic system
pressure
6.2 DEFINITIONS
Driving cycle counter) -The starts since first set
counter indicates the number of driving cycles since
the first occurrence of an error.
8
GENERAL INFORMATION

Symptom:
LR WHEEL SPIN CAN MESSAGE NOT VALID
POSSIBLE CAUSES
ABS WHEEL SPEED SENSOR DTCS PRESENT
ABS CONTROL MODULE
SHIFT LEVER ASSEMBLY
TEST ACTION APPLICABILITY
1 With the DRBIIIt, read ABS DTCs.
Are there any CAN bus or Wheel Speed Sensor DTCs present?All
Ye s!Refer to the ABS category and perform the appropriate symptom.
No!Go To 2
2 Replace the ABS Control Module per the Service Information.
Verify if the DTC returns.
NOTE: It may be necessary to drive the vehicle to verify the repair.
Does the DTC return?All
Ye s!Replace the Shift Lever Assembly per the Service Information.
No!Test Complete.
20
SHIFT LEVER ASSEMBLY

Symptom:
RR WHEEL SPIN CAN MESSAGE NOT VALID
POSSIBLE CAUSES
ABS WHEEL SPEED SENSOR DTCS PRESENT
ABS CONTROL MODULE
SHIFT LEVER ASSEMBLY
TEST ACTION APPLICABILITY
1 With the DRBIIIt, read ABS DTCs.
Are there any CAN bus or Wheel Speed Sensor DTCs present?All
Ye s!Refer to the ABS category and perform the appropriate symptom.
No!Go To 2
2 Replace the ABS Control Module per the Service Information.
Verify if the DTC returns.
NOTE: It may be necessary to drive the vehicle to verify the repair.
Does the DTC return?All
Ye s!Replace the Shift Lever Assembly per the Service Information.
No!Test Complete.
22
SHIFT LEVER ASSEMBLY

Symptom:
ABS LF SENSOR MESSAGE
When Monitored and Set Condition:
ABS LF SENSOR MESSAGE
When Monitored: Valid ABS CAN messages received at least once and the CAN Bus
circuit, ABS CAN Message Missing, ABS CAN Message Incorrect are not active
Set Condition: ABS signal9Wheel Speed Front Left9not valid or ABS has detected a
sensor failure.
POSSIBLE CAUSES
CAN BUS CIRCUIT DTC PRESENT
ABS DTCS PRESENT
ABS CONTROL MODULE - ABS LF SENSOR MESSAGE
TCM - ABS LF SENSOR MESSAGE
TEST ACTION APPLICABILITY
1NOTE: Low fluid level can be the cause of many transmission problems. If
the fluid level is low locate and repair the leak then check and adjust the
fluid level per the service information.
NOTE: Always perform diagnostics with a fully charged battery to avoid
false symptoms.
With the DRBIIIt, read the engine DTCs. Check and repair all engine DTCs prior to
performing transmission symptom diagnostics.
With the DRBIIIt, read and record all Transmission DTCs.
NOTE: Check connectors - Clean/repair as necessary. Poor pin to terminal
connections can set DTCs.
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.
Repair as necessary.
Most DTCs set on start up but some must be set by driving the vehicle such that all
diagnostic monitors have run.
Note: Verify flash level of transmission controller. Some problems are
corrected by software upgrades to the transmission controller.
NOTE: Check for any Technical Service Bulletins that may apply.
Perform this procedure prior to Symptom diagnosis.All
Continue
Go To 2
2 Ignition on, engine not running.
With the DRBIIIt, read Transmission DTCs.
NOTE: If the DTC, CAN BUS CIRCUIT, is present, perform diagnostics on
that symptom first.
Is the DTC, CAN BUS CIRCUIT, present?All
Ye s!Refer to the Transmission category and perform the appropriate
symptom.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
No!Go To 3
38
TRANSMISSION - NAG1

TEST ACTION APPLICABILITY
3 Ignition on, engine not running.
With the DRBIIIt, read ABS DTCs.
Are there any ABS DTCs present?All
Ye s!Refer to the BRAKE category and perform the appropriate
symptom.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
No!Go To 4
4 Turn the ignition off to the lock position.
Replace the ABS Control Module per the Service Information.
With the DRBIIIt, erase Transmission DTCs.
Road test the Vehicle.
With the DRBIIIt, read Transmission DTCs.
Does the DTC, ABS LF SENSOR MESSAGE, reset?All
Ye s!Replace the Transmission Control Module.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
No!Test complete.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
39
TRANSMISSION - NAG1
ABS LF SENSOR MESSAGE ÐContinued