Dodge Ram Truck 1500-2500-3500. Manual — part 1725
P0720-LOW OUTPUT SPEED SENSOR - RPM ABOVE 15 MPH (DIESEL) (CONTINUED)
10.
CHECK THE OUTPUT SPEED SENSOR
Measure the resistance between the terminals of the Output Speed
Sensor.
Is the resistance between 300.0 and 1200.0 ohms?
Yes
>> Using the schematics as a guide, check the Engine Con-
trol Module (ECM) pins, terminals, and connectors for cor-
rosion, damage, or terminal push out. Pay particular
attention to all power and ground circuits. If no problems
are found, replace and program the ECM per the Service
Information. (Refer to 8 - ELECTRICAL/ELECTRONIC
CONTROL MODULES/ENGINE CONTROL MODULE -
REMOVAL)
Perform RE TRANSMISSION VERIFICATION TEST VER -
1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 48RE - STANDARD PROCEDURE)
No
>> Replace the Output Speed Sensor.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
11.
INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.
Use the Freeze Frame Data to help duplicate the conditions in which the DTC originally set. Pay particular attention
to the DTC set conditions, such as, VSS, MAP, ECT, and Load
Using the schematics as a guide, visually inspect the related wiring harness. Look for any chafed, pierced, pinched,
or partially broken wires.
Visually inspect the related wiring harness connectors. Look for broken, bent, pushed out, or corroded terminals.
Wiggle the wiring and connectors while checking for any possible open or shorted circuits.
Check for any Service Information Tune-ups or Technical Service Bulletins that may apply.
Were there any problems found?
Yes
>> Repair as necessary.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
No
>> Test Complete.
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AUTOMATIC TRANSMISSION - 48RE - DIESEL - ELECTRICAL DIAGNOSTICS
DR/DH
P0748-PRESSURE SOL CONTROL/TRANS RELAY CIRCUITS (DIESEL)
DR/DH
AUTOMATIC TRANSMISSION - 48RE - DIESEL - ELECTRICAL DIAGNOSTICS
21 - 833
P0748-PRESSURE SOL CONTROL/TRANS RELAY CIRCUITS (DIESEL) (CONTINUED)
For the Transmission circuit diagram (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 48RE - SCHE-
MATICS AND DIAGRAMS)
For a complete wiring diagramRefer to Section 8W
Theory of Operation
The Governor Pressure Solenoid is used to control governor pressure. Governor pressure is used to shift between
first, second, and third gear.
•
When Monitored:
Continuously with the ignition on.
•
Set Condition:
This DTC will set if the ECM monitored voltage detected on the Governor Pressure Solenoid Control circuit is
different than the expected voltage. Note: To clear this DTC, it is necessary to drive the vehicle at a sustained
speed which would allow the TCC and/or Overdrive Clutch to operate.
Possible Causes
FUSED B+ CIRCUIT OPEN
(T16) TRANSMISSION CONTROL RELAY OUTPUT CIRCUIT OPEN
(T16) TRANSMISSION CONTROL RELAY OUTPUT CIRCUIT SHORT TO GROUND
(T118) GOVERNOR PRESSURE SOLENOID CONTROL CIRCUIT OPEN
(T118) GOVERNOR PRESSURE SOLENOID CONTROL CIRCUIT SHORT TO GROUND
(T118) GOVERNOR PRESSURE SOLENOID CONTROL CIRCUIT SHORT TO VOLTAGE
(T118) GOVERNOR PRESSURE SOLENOID CONTROL CIRCUIT SHORT TO ANOTHER CIRCUIT
TRANSMISSION CONTROL RELAY - POOR CONTACTS
GOVERNOR PRESSURE SOLENOID
ENGINE CONTROL MODULE
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
Diagnostic Test
1.
CHECK IF THE DTC P0882 IS PRESENT
Ignition on, engine not running.
With the scan tool, read Engine DTCs.
Is the DTC P0882 present also?
Yes
>> Refer to the Transmission category and perform the appropriate symptom. (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 48RE - DIAGNOSIS AND TESTING)
No
>> Go To 2
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AUTOMATIC TRANSMISSION - 48RE - DIESEL - ELECTRICAL DIAGNOSTICS
DR/DH
P0748-PRESSURE SOL CONTROL/TRANS RELAY CIRCUITS (DIESEL) (CONTINUED)
2.
CHECK IF THE DTC IS CURRENT
With the scan tool, read Engine DTCs.
Record the Freeze Frame data for the reported DTC.
With the scan tool, erase DTCs.
Turn the ignition off to the lock position.
Using the Freeze Frame data recorded earlier, try to duplicate the conditions in which the DTC originally set.
NOTE: It may be necessary to road test the vehicle to duplicate the original set conditions.
With the scan tool, read Engine DTCs.
Did the DTC reset?
Yes
>> Go To 3
No
>> Go To 12
3.
CHECK THE (T16) TRANSMISSION CONTROL RELAY OUTPUT CIRCUIT
Turn the ignition off to the lock position.
Disconnect the Transmission Solenoid Assembly harness connector.
NOTE: Check connectors - Clean/repair as necessary.
Ignition on, engine not running.
With the scan tool, actuate the Transmission Control Relay.
Using a 12-volt test light connected to ground, check the (T16) Trans-
mission Control Relay Output circuit in the Transmission Solenoid
Assembly harness connector.
NOTE: The test light must illuminate brightly. Compare the bright-
ness to that of a direct connection to the battery.
Does the test light cycle on and off and illuminate brightly?
Yes
>> Go To 4
No
>> Go To 9
DR/DH
AUTOMATIC TRANSMISSION - 48RE - DIESEL - ELECTRICAL DIAGNOSTICS
21 - 835
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