Dodge Durango (HB). Manual — part 1248
P0720-OUTPUT SPEED SENSOR CIRCUIT (CONTINUED)
9.
INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.
Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
Wiggle the wires while checking for shorted and open circuits.
With the scan tool, check the EATX DTC EVENT DATA to help identify the conditions in which the DTC was set.
Were there any problems found?
Yes
>> Repair as necessary.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1.
No
>> Test Complete.
HB
AUTOMATIC TRANSMISSION 545RFE - ELECTRICAL DIAGNOSTICS
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P0725-ENGINE SPEED SENSOR CIRCUIT
For the Transmission circuit diagram (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE -
SCHEMATICS AND DIAGRAMS).
For a complete wiring diagram Refer to Section 8W.
•
When Monitored:
Continuously every 7 msec with the ignition on and engine running.
•
Set Condition:
This DTC will set when the calculated engine speed is less than 390 RPM with the engine running, or greater
than 8000 RPM, for the period of 2.0 seconds. The PCM will place the Transmission in Limp-in when this DTC
is set. Note: This is not a Transmission Input Speed Sensor DTC.
Possible Causes
RELATED ENGINE DTC’S PRESENT
CRANK POSITION SENSOR OR WIRING
POWERTRAIN CONTROL MODULE
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - DIAGNOSIS AND TESTING).
Theory of Operation
The Transmission Control System calculates the engine RPM by directly reading the engine crank position sensor.
It compares the calculated value to the engine speed sensor signal transmitted from the Engine Control System
over the controllers internal bus. The calculated engine RPM is also compared to a minimum and a maximum value.
Note: Due to the integration of the Powertrain Control Module (PCM) and Transmission Control Module
(TCM), bus communication between the modules is internal and unserviceable.
Diagnostic Test
1.
RELATED ENGINE DTCS PRESENT
NOTE: This is not a Transmission Input Speed Sensor DTC.
Ignition on, engine not running.
With the scan tool, read all Engine DTC’s. This includes any active or stored or one trip DTCs.
Are there any engine RPM related DTCs present?
Yes
>> Refer to the Powertrain category and perform the appropriate symptom.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1.
No
>> Go To 2
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AUTOMATIC TRANSMISSION 545RFE - ELECTRICAL DIAGNOSTICS
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P0725-ENGINE SPEED SENSOR CIRCUIT (CONTINUED)
2.
VERIFY IF THE DTC IS CURRENT
Ignition on, engine not running.
With a scan tool, read and record all EATX DTC EVENT DATA.
With the scan tool, erase all active and stored transmission DTCs. (Note: it may be necessary to perform a battery
disconnect with the scan tool to clear EATX DTC EVENT DATA.)
Using the EATX DTC EVENT DATA, duplicate the conditions in which the original DTC set.
With the scan tool, read transmission and engine DTCs.
NOTE: Refer to all engine DTCs first in the following question.
Pick the answer below that best describes your findings, (this includes one trip failures).
Transmission DTC P0725 set
Using the schematics as a guide, check the Powertrain Control Module (PCM) terminals for corrosion,
damage, or terminal push out. Also check the Crank Position sensor and wiring. Pay particular attention
to all power and ground circuits. If no problems are found, replace the PCM per the Service Information.
With the scan tool, perform QUICK LEARN.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1.
Engine DTC set
Refer to the Driveability category and perform the appropriate symptom.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1.
No DTC set at all
Go To 3
3.
INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.
Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
Wiggle the wires while checking for shorted and open circuits.
With the scan tool, check the EATX DTC EVENT DATA to help identify the conditions in which the DTC was set.
Were there any problems found?
Yes
>> Repair as necessary.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1.
No
>> Test Complete.
HB
AUTOMATIC TRANSMISSION 545RFE - ELECTRICAL DIAGNOSTICS
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P0731-GEAR RATIO ERROR IN 1ST
For the Transmission circuit diagram (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE -
SCHEMATICS AND DIAGRAMS).
For a complete wiring diagram Refer to Section 8W
•
When Monitored:
Continuously with the ignition on, engine running, with the transmission in gear.
•
Set Condition:
If the ratio of the Input RPM to the Output RPM does not match the current gear ratio. This DTC can take up
to five minutes of problem identification before illuminating the MIL
Possible Causes
CUT UD PISTON SEAL
LOW FLUID LEVEL
CRACKED OR MISINSTALLED PRIMARY OIL FILTER OR SEAL
STUCK OR STICKING MAIN REGULATOR VALVE
FAILED OVERRUNNING CLUTCH
CUT UD ACCUMULATOR SEAL RING
BROKEN UD ACCUMULATOR PISTON
BROKEN REACTION SHAFT SUPPORT SEAL RING
LOW LINE PRESSURE
BROKEN / MISSING MAIN VALVE BODY BLEED ORIFICE
BROKEN / MISSING DRIBBLER ORIFICE ASSEMBLY IN REACTION SHAFT SUPPORT
POOR MACHINING ON PUMP VALVE BODY FACE
INPUT SPEED SENSOR AND RELATED WIRING
TRANSMISSION SOLENOID/TRS ASSEMBLY
POWERTRAIN CONTROL MODULE
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - DIAGNOSIS AND TESTING).
Theory of Operation
The transmission system uses two speed sensors, one to measure input RPM and one to measure output RPM.
These inputs are essential for proper transmission operation. Therefore, the integrity of this data is verified through
the following checks:
1) Once in a particular gear, if the gear ratio varies from the correct gear ratio, the corresponding in-gear trouble
code is set (DTCs P0731–36).
2) An excessive change in input or output speeds indicating signal intermittent may result in the DTCs P0715 and/or
P0720 being set.
3) If the common speed sensor ground circuit is lost, both sensor inputs will read the pulses from the input speed
sensor when at a stop in neutral. Since the input speed sensor reads 60 teeth from the input clutch hub and the
output speed sensor reads 30 teeth from the park gear, the result is an apparent speed ratio of 1:2 and may cause
the DTC P1794 to set.
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AUTOMATIC TRANSMISSION 545RFE - ELECTRICAL DIAGNOSTICS
HB
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