2006 DODGE RAM SRT-10 ECO mode

Theory of Operation
The tow/haul overdrive OFF (control) switch is located in the shift lever arm. The switch is a momentary contact
device that signals the ECM/PCM to toggle current status of the overdrive function. At ignition on, overdrive oper-
ation is allowed. Pressing the Tow/Haul Overdrive Off switch once causes the Tow/haul Overdrive OFF mode to be
entered and the Tow/Haul lamp to be illuminated. Pressing the switch a second time causes normal overdrive oper-
ationtoberestoredandtheTow/haullamptobeturnedoff.TheTow/haulOverdrive OFF mode defaults to ON after
the ignition switch is cycled OFF and ON. The normal position for the control switch is the ON position. The switch
must be in this position to energize the solenoid and allow a 3-4 upshift. The control switch indicator light illuminates
only when the Tow/haul Overdrive Off switch is turned to the OFF position, or when illuminated by the transmission
control module.
Possible Causes
TOW/HAUL OVERDRIVE OFF SWITCH SENSE CIRCUIT SHORT TO GROUND
TOW/HAUL OVERDRIVE OFF SWITCH
ENGINE CONTROL MODULE
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 8 - ELECTRI-
CAL/ELECTRONIC CONTROL MODULES/TRANSMISSION CONTROL MODULE - DIAGNOSIS AND TESTING)
Diagnostic Test
1.TOW/HAUL OVERDRIVE OFF SWITCH SENSE CIRCUIT SHORT TO GROUND
Turn the ignition off.
Disconnect the ECM C2 harness connector.
Disconnect the Tow/Haul OverdriveOff switch harness connector.
Measure the resistance between ground and the Tow/Haul Overdrive
Off switch sense circuit in the ECM C2 harness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Repair the Tow/Haul Overdrive Off switch sense circuit for a
short to ground.
Perform RE TRANSMISSION VERIFICATION TEST VER -
1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Go To 2

SWITCH-TOW/HAUL OVERDRIVE
DESCRIPTION
The tow/haul overdrive OFF (control) switch is located
in the shift lever arm. The switch is a momentary con-
tact device that signals the PCM to toggle current sta-
tus of the overdrive function.
OPERATION
At key-on, overdrive operation is allowed. Pressing the switch once causes the tow/haul overdrive OFF mode to be
entered and the Tow/Haul lamp to be illuminated. Pressing the switch a second time causes normal overdrive oper-
ationtoberestoredandthetow/haullamptobeturnedoff.Thetow/hauloverdrive OFF mode defaults to ON after
the ignition switch is cycled OFF and ON. The normal position for the control switch is the ON position. The switch
must be in this position to energize the solenoid and allow a 3-4 upshift. The control switch indicator light illuminates
only when the tow/haul overdrive switch is turned to the OFF position, or when illuminated by the transmission
control module.
DIAGNOSIS AND TESTING - OVERDRIVE ELECTRICAL CONTROLS
The tow/haul overdrive off switch, valve body solenoid, case connectors and related wiring can all be tested with a
12 volt test lamp or a volt/ohmmeter. Check continuity of each component when diagnosis indicates this is neces-
sary.
Switch and solenoid continuity shouldbe checked whenever the transmission fails to shift into fourth gear range.
REMOVAL
1. Using a plastic trim tool, remove the tow/haul over-
drive off switch retainer (2) from the shift lever (1).

When Monitored:
With the ignition on.
Set Condition:
Transfer Case Range Select Switch voltage less than 0.1568 volts for 5 seconds
Possible Causes
(K77) 5 VOLT SELECTOR SWITCH SUPPLY CIRCUIT OPEN
(K77) 5 VOLT SELECTOR SWITCH SUPPLY CIRCUIT SHORTED TO GROUND
(K977) MODE SELECT CIRCUIT OPEN
(K977) MODE SELECT CIRCUIT SHORT TO GROUND
TRANSFER CASE SELECTOR SWITCH
INSTRUMENT CLUSTER
Diagnostic Test
1.TRANSFER CASE SWITCH VOLTAGE LESS THAN 0.2 VOLTS
Ignition on, engine not running.
With the scan tool under Instrument Cluster, read the Transfer Case Switchvoltage.
Is the voltage less than 0.2 volts?
Ye s>>
Go To 2
No>>
Go To 8
2.(K77) 5 VOLT SELECTOR SWITCH SUPPLY CIRCUIT VOLTAGE LESS THAN 0.2 VOLTS
Turn the ignition off to the lock position.
Disconnect the Transfer Case Selector Switch harness connector.
Ignition on, engine not running.
Measure the voltage of the (K77) 5 Volt Selector Switch Supply circuit.
Is the voltage less than 0.2 volts?
Ye s>>
Go To 3
No>>
Go To 5

When Monitored:
With the ignition on.
Set Condition:
Transfer Case Range Select Switch voltage greater than 4.86 volts for 5 seconds
Possible Causes
(K77) 5 VOLT SELECTOR SWITCH SUPPLY CIRCUIT SHORTED TO VOLTAGE
(K977) MODE SELECT CIRCUIT SHORTED TO VOLTAGE
(K977) MODE SELECT CIRCUIT OPEN
(Z905) TRANSFER CASE SELECTOR SWITCH GROUND CIRCUIT OPEN
TRANSFER CASE SELECTOR SWITCH
INSTRUMENT CLUSTER
Diagnostic Test
1.TCASE SWITCH VOLTAGE ABOVE 4.8 VOLTS
Ignition on, engine not running.
With the scan tool under Instrument Cluster, read the Transfer Case Switchvoltage.
Is the volage above 4.8 volts?
Ye s>>
Go To 2
No>>
Go to 8
2.(K77) 5 VOLT SELECTOR SWITCH SUPPLY CIRCUIT SHORTED TO VOLTAGE
Turn the ignition off to the lock position.
Disconnect the Transfer Case Selector Switch harness connector.
Disconnect the Instrument Cluster C4 harness connector.
Ignition on, engine not running.
Measure the voltage of the (K77) 5 Volt Selector Switch Supply circuit.
Is there any voltage present?
Ye s>>
Repair the (K77) 5 Volt Selector Switch Supply circuit for a
short to voltage.
Perform the TRANSFER CASE VERIFICATION TEST-VER
1. (Refer to 21 - TRANSMISSION/TRANSAXLE/TRANSFER
CASE - STANDARD PROCEDURE)
No>>
Go to 3

3.(K977) MODE SELECT CIRCUIT SHORTED TO VOLTAGE
Turn the ignition off to the lock position.
Disconnect the Instrument Cluster C3 harness connector.
Ignition on, engine not running.
Measure the voltage of the (K977) Mode Select circuit.
Is there any voltage present?
Ye s>>
Repair the (K977) Mode Select circuit for a short to voltage.
Perform the TRANSFER CASE VERIFICATION TEST-VER
1. (Refer to 21 - TRANSMISSION/TRANSAXLE/TRANSFER
CASE - STANDARD PROCEDURE)
No>>
Go to 4
4.TRANSFER CASE SELECTOR SWITCH
Turn the ignition off to the lock position.
Reconnect the Instrument Cluster C3 harness connector.
Reconnect the Instrument Cluster C4 harness connector.
Ignition on, engine not running.
With the scan tool under Instrument Cluster, read the Transfer Case Switchvoltage.
Is the voltage equal to 0.0 volts?
Ye s>>
Replace the Transfer Case Selector Switch.
Perform the TRANSFER CASE VERIFICATION TEST-VER 1. (Refer to 21 - TRANSMISSION/TRANS-
AXLE/TRANSFER CASE - STANDARD PROCEDURE)
No>>
Go to 5

When Monitored:
Ignition on. Battery voltage between 9.0 and 16.0 volts.
Set Condition:
The TIPM detects a short to ground on the Transfer Case Position Sensor Signal circuit for 2.0 seconds.
Possible Causes
(T103) 5 VOLT SUPPLY CIRCUIT OPEN
(T103) 5 VOLT SUPPLY CIRCUIT SHORTED TO GROUND
(D201) MODE SENSOR A CIRCUIT SHORTED TO GROUND
(D201) MODE SENSOR A CIRCUIT SHORTED TO (G180) SENSOR RETURN CIRCUIT
SHIFT MOTOR/MODE SENSOR ASSEMBLY
TOTALLY INTERGRATED POWER MODULE (TIPM)
Diagnostic Test
1.T-CASE POSITION SENSOR VOLTAGE BELOW 0.2 VOLTS
Ignition on, engine not running.
With the scan tool under TIPM, read the T-Case Position Sensor voltage.
Is the voltage below 0.2 volts?
Ye s>>
Go to 2
No>>
Go to 8
2.(T103) 5 VOLT SUPPLY CIRCUIT VOLTAGE BELOW 0.2 VOLTS
Turn the ignition off to the lock position.
Disconnect the Shift Motor/Mode Sensor harness connector.
Ignition on, engine not running.
Measure the voltage of the (T103) 5-volt Supply circuit at the Shift
Motor/Mode Sensor harness connector.
Is the voltage below 0.2 volts?
Ye s>>
Go to 3
No>>
Go to 5

When Monitored:
With the ignition on. Battery voltage between 9.0 and 16.0 volts
Set Condition:
The TIPM detects 5.0 volts on the Transfer Case Range Position Sensor Signal circuit for 2.0 seconds when
voltage should not be present.
Possible Causes
(T103) 5 VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE
(D201) MODE SENSOR A CIRCUIT SHORTED TO VOLTAGE
(D201) MODE SENSOR A CIRCUIT OPEN
(G180) TIPM SENSOR RETURN CIRCUIT OPEN
SHIFT MOTOR/MODE SENSOR ASSEMBLY
TOTALLY INTEGRATED POWER MODULE (TIPM)
Diagnostic Test
1.T-CASE POSITION SENSOR VOLTAGE ABOVE 4.8 VOLTS
Ignition on, engine not running.
With the scan tool under TIPM, read the T-Case Position sensor voltage.
Is the voltage above 4.8 volts?
Ye s>>
Go To 2
No>>
Go to 7
2.(T103) 5 VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE
Turn the ignition off to the lock position.
Disconnect the Shift Motor/Mode sensor harness connector.
Ignition on, engine not running.
Measure the voltage of the (T103) 5 Volt Supply circuit.
Is the voltage above 5.5 volts?
Ye s>>
Repair the (T103) 5 Volt Supply circuit for a short to volt-
age.
Perform the TRANSFER CASE VERIFICATION TEST-VER
1. (Refer to 21 - TRANSMISSION/TRANSAXLE/TRANSFER
CASE - STANDARD PROCEDURE)
No>>
Go to 3

3.ACTUATE T-CASE MOTOR
Reconnect the TIPM C4 harness connector.
Ignition on, engine not running.
With the scan tool, actuate the T-Case Motor Brake.
Using a 12-volt test light connected to 12-volts, check the (T300) Trans-
fer Case Motor Brake Signal circuit at the Shift Motor/Mode Sensor
Assembly harness connector.
NOTE: Compare the brightness to that of a direct connection to
the battery.
Does the test light illuminate brightly?
Ye s>>
Replace the Totally Integrated Power Module (TIPM) in
accordance with the Service Information.
Perform the TRANSFER CASE VERIFICATION TEST-VER
1. (Refer to 21 - TRANSMISSION/TRANSAXLE/TRANSFER
CASE - STANDARD PROCEDURE)
No>>
Go to 4
4.(T300) TRANSFER CASE MOTOR BRAKE SIGNAL CIRCUIT OPEN
Turn the ignition off to the lock position.
Disconnect the TIPM C4 harness connector.
Measure the resistance of the (T300) Transfer Case Motor Brake Signal
circuit between the TIPM C4 harness connector and the Shift Motor/
Mode Sensor Assembly harness connector.
Is the resistance above 5.0 ohms?
Ye s>>
Repair the (T300) Transfer Case Motor Brake Signal circuit
for an open circuit or high resistance.
Perform the TRANSFER CASE VERIFICATION TEST-VER
1. (Refer to 21 - TRANSMISSION/TRANSAXLE/TRANSFER
CASE - STANDARD PROCEDURE)
No>>
Replace the Totally Integrated Power Module (TIPM) in
accordance with the Service Information.
Perform the TRANSFER CASE VERIFICATION TEST-VER
1. (Refer to 21 - TRANSMISSION/TRANSAXLE/TRANSFER
CASE - STANDARD PROCEDURE)
5.INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.
While monitoring the scan tool data relative to this circuit, wiggle test the wiring and connectors.
Look for the data to change or for the DTC to reset during the wiggle test.
Were any problems found?
Ye s>>
Repair as necessary.
Perform the TRANSFER CASE VERIFICATION TEST-VER 1. (Refer to 21 - TRANSMISSION/TRANS-
AXLE/TRANSFER CASE - STANDARD PROCEDURE)
No>>
Te s t c o m p l e t e .