Mercedes-Benz Sprinter / Dodge Sprinter. Manual — part 550

Symptom:

INTERNAL CONTROLLER

When Monitored and Set Condition:

INTERNAL CONTROLLER

When Monitored:

Always monitored with system active at each ignition cycle

Set Condition:

This code is set whenever Transmission Control Module (TCM) senses an

internal error. If this Internal Controller DTC is set with any Solenoid DTC’s repair the
Solenoid DTC’s first, erase all DTC’s, then verify the Internal Controller DTC sets before
replacing the TCM.

POSSIBLE CAUSES

TCM - INTERNAL ERROR

TEST

ACTION

APPLICABILITY

1

If there are no possible causes remaining, view repair.

All

Repair

The Transmission Control Module is reporting internal errors and
must be replaced.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.

82

TRANSMISSION - NAG1

Symptom:

INVALID CONTROL MODULE VERSION

POSSIBLE CAUSES

TRANSMISSION CONTROL MODULE

INVALID CONTROL MODULE

TEST

ACTION

APPLICABILITY

1

NOTE: 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 DRBIII

t, read the engine DTCs. Check and repair all engine DTCs prior to

performing transmission symptom diagnostics.
With the DRBIII

t, 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

Validate if the TCM part number and flash is correct for the vehicle.
Is the TCM part number and flash correct for the vehicle?

All

Yes

→ Replace the Transmission Control Module per the Service Infor-

mation.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.

No

→ Flash the controller is applicable. If the controller has the wrong

part number or cannot be flashed, replace the TCM per the
Service Information.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.

83

TRANSMISSION - NAG1

Symptom:

MODULATING PRESSURE SOLENOID CIRCUIT

When Monitored and Set Condition:

MODULATING PRESSURE SOLENOID CIRCUIT

When Monitored:

Always monitored with system active at each ignition cycle.

Set Condition:

If the TCM detects a short to ground or battery on the solenoid control

circuit, shorted solenoid, open solenoid, or an open or shorted solenoid control circuit driver
in the TCM.

POSSIBLE CAUSES

INTERMITTENT WIRING AND CONNECTORS

MOD. PRESS SOLENOID CONTROL CIRCUIT OPEN

MOD. PRESS SOLENOID CONTROL CIRCUIT SHORT TO GROUND

MOD. PRESS SOLENOID CONTROL CIRCUIT SHORT TO OTHER CIRCUITS

MOD PRESS SOLENOID

TCM - MOD. PRESS SOLENOID CIRCUIT

TEST

ACTION

APPLICABILITY

1

NOTE: 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 DRBIII

t, read the engine DTCs. Check and repair all engine DTCs prior to

performing transmission symptom diagnostics.
With the DRBIII

t, 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

84

TRANSMISSION - NAG1

TEST

ACTION

APPLICABILITY

2

Ignition on, engine not running.
With the DRBIII

t, erase DTCs.

With the DRBIII

t, perform the Solenoid Test

With the DRBIII

t, read DTCs.

Did the DTC, Mod Press SOLENOID CIRCUIT, reset?

All

Yes

→ Go To 3

No

→ Go To 7

3

Turn the ignition off to the lock position.
Disconnect the Transmission Control Module C2 harness connector.
Disconnect the Transmission Solenoid Assembly harness connector
Note: Check connectors - Clean/repair as necessary.
Measure the resistance of the Mod. Press Solenoid Control circuit from the TCM C2
harness connector to the Transmission Solenoid Assembly harness connector.
Is the resistance above 5.0 ohms?

All

Yes

→ Repair the Mod. Press Solenoid Control circuit for an open.

Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.

No

→ Go To 4

4

Turn the ignition off to the lock position.
Disconnect the Transmission Control Module C2 harness connector.
Disconnect the Transmission Solenoid Assembly harness connector.
Note: Check connectors - Clean/repair as necessary.
Measure the resistance between ground and the Mod. Press Solenoid Control circuit.
Is the resistance below 5.0 ohms?

All

Yes

→ Repair the Mod. Press Solenoid Control circuit for a short to

ground.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.

No

→ Go To 5

5

Turn the ignition off to the lock position.
Disconnect the Transmission Control Module C2 harness connector.
Disconnect the Transmission Solenoid Assembly harness connector.
Note: Check connectors - Clean/repair as necessary.
Measure the resistance of the Mod Press Solenoid Control circuit to all other circuits
in the Transmission Solenoid Assembly harness connector.
Is the resistance below 5.0 ohms between any other circuit?

All

Yes

→ Repair the Mod. Press Solenoid Control circuit for a short to other

circuits.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.

No

→ Go To 6

85

TRANSMISSION - NAG1

MODULATING PRESSURE SOLENOID CIRCUIT —

Continued