Recently, my husband's 2000 Durango (5.2L Engine, 2WD) put out the code P0748. Along with the code, it will only drive in 3rd gear and does not shift from that whatsoever. We read online and assumed the problem was the governor pressure sensor and solenoid. He just replaced those, changed the transmission fluid, transmission filter and tried to clear the code. After doing all of those things, the code still shows and the car still won't shift out of 3rd gear. I did a more reading online that it maybe the TPS but, that was changed 7 months ago so we don't think it could be that.
Hopefully, someone can offer my some advice?
Thanks!

 

Welcome to DF
Here is some information, but you may need a scanner to perform these procedures.

Symptom:
P0748-PRESSURE SOL CONTROL/TRANS RELAY CIRCUITS
When Monitored and Set Condition:
P0748-PRESSURE SOL CONTROL/TRANS RELAY CIRCUITS
When Monitored: Continuously with the key on.
Set Condition: This code will set if the voltage detected on the Governor Pressure
Solenoid Control circuit at the PCM is different than the expected voltage.
POSSIBLE CAUSES
P1765 DTC PRESENT
INTERMITTENT GOVERNOR PRESSURE SOLENOID
TRANSMISSION RELAY OUTPUT
FUSED B+ CIRCUIT OPEN
GOVERNOR PRESSURE SOLENOID CONTROL CIRCUIT OPEN
GOVERNOR PRESSURE SOLENOID CONTROL CIRCUIT OPEN INTERNAL
TRANSMISSION CONTROL RELAY OUTPUT CIRCUIT OPEN
GOVERNOR PRESSURE SOLENOID CONTROL CIRCUIT SHORT TO GROUND
GOVERNOR PRESSURE SOLENOID CONTROL CIRCUIT SHORT TO GROUND INTERNAL
TRANSMISSION RELAY OUTPUT CIRCUIT SHORT TO GROUND
GOVERNOR PRESSURE SOLENOID CONTROL CIRCUIT SHORT TO VOLTAGE
GOVERNOR PRESSURE SOLENOID CONTROL CIRCUIT SHORT TO SOLENOID CIRCUITS INTERNAL
GOVERNOR PRESSURE SOLENOID CONTROL CIRCUIT SHORT TO OTHER CIRCUITS
GOVERNOR PRESSURE SOLENOID CONTROL CIRCUIT SHORT TO OTHER CIRCUITS INTERNAL
TRANSMISSION CONTROL RELAY - POOR CONTACTS
PCM - GOVERNOR PRESSURE SOLENOID CONTROL CIRCUIT
TEST ACTION APPLICABILITY
1 Ignition on, engine not running.
With the DRBIIIt, read DTCs.
Is the Good Trip Counter for P0748 displayed and equal to 0?
All
Yes ® Go To 2
No ® Go To 18
TEST ACTION APPLICABILITY
2 With the DRBIIIt, read Transmission DTCs.
Is the DTC P1765 present?
All
Yes ® Perform diagnostics on P1765 TRANS 12-VOLT SUPPLY RELAY
CTRL CIRCUIT first before proceeding.
Perform TRANSMISSION VERIFICATION TEST VER - 1.
No ® Go To 3
3 With the DRBIIIt, read Transmission DTCs.
Are DTCs P0743, P0748 and P0753 present?
All
Yes ® Go To 4
No ® Go To 9
4 Turn the ignition off to the lock position.
Disconnect the Transmission Solenoid Assembly harness connector.
Ignition on, engine not running.
Using a 12-volt test light connected to ground, check the Transmission Control Relay
Output circuit in the Transmission Solenoid Assembly harness connector.
Does the test light illuminate brightly?
All
Yes ® Replace the Transmission Solenoid Assembly in accordance with
the Service Information.
Perform TRANSMISSION VERIFICATION TEST VER - 1.
No ® Go To 5
5 Turn the ignition off to the lock position.
Remove the Transmission Control Relay.
Ignition on, engine not running.
Using a 12-volt test light connected to ground, check the Fused B+ circuit in the
Transmission Control Relay connector.
NOTE: The light must illuminate brightly, if it does not light, or lights dimly,
the circuit must be repaired. If there is any doubt, compare the brightness
when testing the circuit, to the brightness when connected directly to the
battery positive post.
Does the test light illuminate brightly?
All
Yes ® Go To 6
No ® Repair the Fused B+ circuit for an open. If the fuse is open, make
sure to check for a short to ground or excessive resistance in the
Fused B+ circuit and repair as necessary.
Perform TRANSMISSION VERIFICATION TEST VER - 1.
6 Turn the ignition off to the lock position.
Disconnect the Transmission Solenoid Assembly harness connector.
Remove the Transmission Control Relay.
Measure the resistance between ground and the Transmission Relay Control Output
circuit.
Is the resistance below 5.0 ohms?
All
Yes ® Repair the Transmission Relay Output circuit for a short to
ground.
Perform TRANSMISSION VERIFICATION TEST VER - 1.
No ® Go To 7
TEST ACTION APPLICABILITY
7 Turn the ignition off to the lock position.
Disconnect the Transmission Solenoid Assembly harness connector.
Check connectors - Clean/repair as necessary
Ignition on, engine not running.
Connect a jumper wire between the Fused Transmission Relay Output circuit and
Fused B+ in the Transmission Relay connector.
Using a 12-volt test light connected to ground, check the Transmission Relay Control
Output circuit in the Transmission Solenoid Assembly harness connector.
Does the test light illuminate brightly?
All
Yes ® Go To 8
No ® Repair the Fused Transmission Control Relay Output circuit for
an open. If the Fuse is open, make sure to check for a short to
ground or excessive resistance in the Fused Transmission Control
Relay Output circuit and repair as necessary.
Perform TRANSMISSION VERIFICATION TEST VER - 1.
8 Turn the ignition off to the lock position.
Disconnect the Transmission Solenoid Assembly harness connector.
Check connectors - Clean/repair as necessary
Ignition on, engine not running.
Connect a jumper wire between the Transmission Relay Output circuit and the Fused
B+ circuit in the Transmission Relay connector.
Using a 12-volt test light connected to ground, check the Transmission Relay Control
Output circuit in the Transmission Solenoid Assembly harness connector.
Does the test light illuminate brightly?
All
Yes ® Replace the Transmission Control Relay.
Perform TRANSMISSION VERIFICATION TEST VER - 1.
No ® Test Complete.
9 Turn the ignition off to the lock position.
Disconnect the Transmission Solenoid Assembly harness connectors.
Disconnect the PCM harness connector.
Check connectors - Clean/repair as necessary.
Measure the resistance of the Governor Pressure Solenoid Control circuit between
the Transmission Solenoid Assembly harness connector and the PCM harness
connector.
Is the resistance below 5.0 ohms?
All
Yes ® Go To 10
No ® Repair the Governor Pressure Solenoid Control circuit for an
open.
Perform TRANSMISSION VERIFICATION TEST VER - 1.
10 Turn the ignition off to the lock position.
Disconnect the Transmission Solenoid Assembly harness connector.
Disconnect the PCM harness connectors.
Check connectors - Clean/repair as necessary
Measure the resistance between ground and the Governor Pressure Solenoid Control
circuit in the PCM harness connector.
Is the resistance below 5.0 ohms?
All
Yes ® Repair the Governor Pressure Solenoid Control circuit for a short
to ground.
Perform TRANSMISSION VERIFICATION TEST VER - 1.
No ® Go To 11
TEST ACTION APPLICABILITY
11 Turn the ignition off to the lock position.
Disconnect the PCM harness connectors.
Disconnect the Transmission Solenoid Assembly harness connector.
Ignition on, engine not running.
Measure the voltage of the Governor Pressure Solenoid Control circuit.
Is the voltage above 0.5 volt?
All
Yes ® Repair the Governor Solenoid Control circuit for a short to
voltage.
Perform TRANSMISSION VERIFICATION TEST VER - 1.
No ® Go To 12
12 Turn the ignition off to the lock position.
Disconnect the PCM harness connectors.
Disconnect the Transmission Solenoid Assembly harness connector.
Remove the Transmission Control Relay.
Check connectors - Clean/repair as necessary
Measure the resistance between the Governor Pressure Solenoid Control circuit and
all other circuits in the Transmission Solenoid Assembly harness connector.
Is the resistance below 100 kohms between any two circuits?
All
Yes ® Repair as necessary.
Perform TRANSMISSION VERIFICATION TEST VER - 1.
No ® Go To 13
13 Turn the ignition off to the lock position.
Disconnect the PCM harness connectors.
Remove the Transmission Control Relay.
Measure the resistance of the Governor Pressure Solenoid Control circuit between
the PCM harness connector and the Transmission Control Relay Output circuit
connector.
Is the resistance between 3.0 ohms and 6.0 ohms
All
Yes ® Go To 14
No ® Replace the Transmission Solenoid Assembly in accordance with
the Service Information.
Perform TRANSMISSION VERIFICATION TEST VER - 1.
14 Turn the ignition off to the lock position.
Disconnect the PCM harness connectors.
Check connectors - Clean/repair as necessary
Measure the resistance between the Governor Pressure Solenoid Control circuit and
ground.
Is the resistance below 5.0 ohms?
All
Yes ® Repair or Replace the Transmission Solenoid Assembly for a short
to ground.
Perform TRANSMISSION VERIFICATION TEST VER - 1.
No ® Go To 15
TEST ACTION APPLICABILITY
15 Turn the ignition off to the lock position.
Disconnect the PCM harness connectors.
Check connectors - Clean/repair as necessary
NOTE: Resistance between the Governor Pressure Solenoid Control circuit
and the listed circuits should be 28 to 68 ohms.
Measure the resistance between the Governor Pressure Solenoid Control circuit and
the...
* TCC Solenoid Control circuit in the PCM harness connector.
* 3-4 shift Solenoid Control circuit in the PCM harness connector.
Is the resistance of both measurements within the range of 28 to 68 ohms?
All
Yes ® Go To 16
No ® Replace Transmission Solenoid Assembly per Service Information.
Perform TRANSMISSION VERIFICATION TEST VER - 1.
16 Turn the ignition off to the lock position.
Disconnect the PCM harness connectors.
Remove the Transmission Control Relay.
Check connectors - Clean/repair as necessary
NOTE: Resistance between the Governor Pressure Solenoid circuit and the
listed circuits should not be below 100 kohms.
Measure the resistance between the Governor Pressure Solenoid Control circuit and
the...
* Transmission 5-volt supply circuit in the C2 PCM harness connector.
* Sensor Ground circuit in the C2 PCM harness connector.
* Transmission Temp Sensor Signal circuit in the PCM harness connector.
* Governor Pressure Sensor Signal circuit in the PCM harness connector.
Are the resistance values for any of the above listed circuits below 100 kohms?
All
Yes ® Replace Transmission Solenoid Assembly per Service Information.
Perform TRANSMISSION VERIFICATION TEST VER - 1.
No ® Go To 17
17 If there are no possible causes remaining, view repair. All
Repair
Replace the Powertrain Control Module in accordance with the
Service Information.
Perform TRANSMISSION VERIFICATION TEST VER - 1.
18 At this time, the conditions required to set the DTC are not present.
NOTE: Use the Freeze Frame Data to help duplicate the conditions that set
the DTC. Pay particular attention to the DTC set conditions, such as, VSS,
MAP, ECT, and Load.
NOTE: Visually inspect the related wiring harness. Look for any chafed,
pierced, pinched, broken, bent, pushed out, corroded terminals, or partially
broken wires.
NOTE: Refer to any technical service bulletins that may apply.
Were any problems found?
All
Yes ® Repair as necessary.
Perform TRANSMISSION VERIFICATION TEST VER - 1.
No ® Test Complete.
End of test.

 

Thank you so much master tech for your advice! We did rent a scanner in hopes to find the problem. My husband finally discovered it was the transmission relay that was bad. After replacing it, everything works fine now and the code is gone. Thank you again for your advice!