Page 3138 of 5267

4.(T13) SPEED SENSOR GROUND CIRCUIT SHORT TO VOLTAGE
With the scan tool in TIPM, actuate the TCM output.
Measure the voltage of the (T13) Speed Sensor Ground circuit.
Is the voltage above 0.5 volts?
Ye s>>
Repair the (T13) Speed Sensor Ground circuit for a short to
voltage.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION
TEST - VER 1. (Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PRO-
CEDURE)
No>>
Go To 5
5.(T52) INPUT SPEED SENSOR SIGNAL CIRCUIT OPEN
With the scan tool in TIPM, stop the actuation the TCM output.
Turn the ignition off to the lock position.
Measure the resistance of the (T52) Input Speed Sensor Signal circuit
between the Input Speed Sensor harness connector and the appropri-
ate terminal of Miller tool #8815.
Is the resistance above 5.0 ohms?
Ye s>>
Repair the (T52) Input Speed Sensor Signal circuit for an
open.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION
TEST - VER 1. (Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PRO-
CEDURE)
No>>
Go To 6
Page 3139 of 5267
6.(T13) SPEED SENSOR GROUND CIRCUIT OPEN
Measure the resistance of the (T13) Speed Sensor Ground circuit
between the Input Speed Sensor harness connector and the appropri-
ate terminal of Miller tool #8815.
Is the resistance above 5.0 ohms?
Ye s>>
Repair the (T13) Speed Sensor Ground circuit for an open.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION
TEST - VER 1. (Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PRO-
CEDURE)
No>>
Go To 7
7.(T52) INPUT SPEED SENSOR SIGNAL CIRCUIT SHORT TO GROUND
Measure the resistance between ground and the Input Speed Sensor
Signal circuit.
Is the resistance below 5.0 ohms?
Ye s>>
Repair the (T52) Input Speed Sensor Signal circuit for a
short to ground.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION
TEST - VER 1. (Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PRO-
CEDURE)
No>>
Go To 8
Page 3140 of 5267

8.(T13) SPEED SENSOR GROUND CIRCUIT SHORT TO GROUND
Measure the resistance between ground and the (T13) Speed Sensor
Ground circuit.
Is the resistance below 5.0 ohms?
Ye s>>
Repair the (T13) Speed Sensor Ground circuit for a short to
ground.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION
TEST - VER 1. (Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PRO-
CEDURE)
No>>
Using the schematics as a guide, check the Powertrain
Control Module (PCM) terminals for corrosion, damage, or
terminal push out. 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. (Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PRO-
CEDURE)
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 specifictothiscircuit.
Wiggle the wires while checking for shorted and open circuits.
With the scan tool, check the DTC EVENT DATA to help identify the conditionsin which the DTC was set.
Were there any problems found?
Ye s>>
Repair as necessary.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
No>>
Te s t C o m p l e t e .
Page 3141 of 5267
P0720-OUTPUT SPEED SENSOR CIRCUIT
For a complete wiring diagramRefer to Section 8W.
Page 3142 of 5267

When Monitored:
The transmission gear ratio is monitored continuously while the transmission is in gear.
Set Condition:
If there is an excessive change in output RPM in any gear. This DTC can take upto five minutes of problem
identification beforeilluminating the MIL.
Possible Causes
(T14) OUTPUT SPEED SENSOR SIGNAL CIRCUIT OPEN
(T13) SPEED SENSOR GROUND CIRCUIT OPEN
(T14) OUTPUT SPEED SENSOR SIGNAL CIRCUIT SHORT TO GROUND
(T13) SPEED SENSOR GROUND CIRCUIT SHORT TO GROUND
(T14) OUTPUT SPEED SENSOR SIGNAL CIRCUIT SHORT TO VOLTAGE
(T13) SPEED SENSOR GROUND CIRCUIT SHORT TO VOLTAGE
OUTPUT SPEED SENSOR
POWERTRAIN CONTROL MODULE
Always perform the 45RFE/545RFE Pre-Diagnostic Troubleshooting Procedure before proceeding. (Refer to
21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
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) When in gear, if the gear ratio does not compare to a known gear ratio, the corresponding in-gear trouble code
is set (codes P0731 through P0736).
2) An excessive change in input or output speeds indicating signal intermittent will result in codes P0715 and/or
P0720 being set.
3) If the common speed sensor ground circuit is lost, both sensor inputs will read the signal from the input speed
sensor at idle in neutral. Since the input speed sensor has 60 teeth and the output speed sensor has 30 teeth, this
results in a an apparent speed ratio of 1:2 and may cause the DTC P1794 to set.
Diagnostic Test
1.CHECK TO SEE IF DTC P0720 IS CURRENT
Turn the ignition off to the lock position.
CAUTION: Properly support the vehicle and raise all drive wheels off the ground.
Release the parking brake.
Start the engine in park.
Place the transmission gear selector in drive, release foot from brake.
WARNING: Be sure to keep hands and feet clear of rotation wheels.
With the scan tool, monitor the Output Speed Sensor RPM.
Is the Output Speed Sensor RPM below 100 RPM?
Ye s>>
Go To 2
No>>
Go To 9
Page 3143 of 5267

2.OUTPUT SPEED SENSOR
Turn the ignition off to the lock position.
Remove the Ignition Switch Feed fuse from the TIPM.
CAUTION: Removal of the Ignition Switch Feed fuse from the TIPM will prevent the vehicle from being
startedingear.
WARNING: The Ignition Switch Feed fuse must be removed from the TIPM. Failure to do so can result in
personal injury or death.
Install the Transmission Simulator, Miller tool #8333.
Ignition on, engine not running.
With the Transmission Simulator, set the selector switch to 3000/1000 andthe Input/Output switch to ON.
With the scan tool, monitor the Input and Output Speed Sensor RPM
Does the Input Speed read 3000 RPM and the Output Speed read 1000 RPM, ± 50 RPM?
Ye s>>
Replace the Output Speed Sensor per the Service Information.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
No>>
Go To 3
3.CHECK THE (T14) OUTPUT SPEED SENSOR SIGNAL CIRCUIT FOR AN OPEN
Turn the ignition off to the lock position.
Disconnect the Transmission Simulator, Miller tool #8333.
Disconnect the PCM harness connectors and connect Miller special tool
#8815.
CAUTION: Do not probe the PCM harness connectors. Probing the
PCM harness connectors will damage the PCM terminals resulting
in poor terminal to pin connection. Install Miller special tool #8815
to perform diagnosis.
Measure the resistance of the (T14) Output Speed Sensor Signal circuit
from the Output Speed Sensor harness connector to the appropriate
terminal of Miller tool #8815.
Is the resistance above 5.0 ohms?
Ye s>>
Repair the (T14) Output Speed Sensor Signal circuit for an
open.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION
TEST - VER 1. (Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PRO-
CEDURE)
No>>
Go To 4
Page 3144 of 5267
4.CHECK THE (T13) SPEED SENSOR GROUND CIRCUIT FOR AN OPEN
Measure the resistance of the (T13) Speed Sensor Ground circuit from
the Output Speed Sensor harness connector to the appropriate terminal
in the Miller tool #8815.
Is the resistance above 5.0 ohms?
Ye s>>
Repair the (T13) Speed Sensor Ground circuit for an open.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION
TEST - VER 1. (Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PRO-
CEDURE)
No>>
Go To 5
5.CHECK THE (T14) OUTPUT SPEED SENSOR SIGNAL CIRCUIT FOR A SHORT TO GROUND
Measure the resistance between ground and the (T14) Output Speed
Sensor Signal circuit.
Is the resistance below 5.0 ohms?
Ye s>>
Repair the (T14) Output Speed Sensor Signal circuit for a
short to ground.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION
TEST - VER 1. (Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PRO-
CEDURE)
No>>
Go To 6
Page 3145 of 5267
6.CHECK THE (T13) SPEED SENSOR GROUND CIRCUIT FOR A SHORT TO GROUND
Measure the resistance between ground and the (T13) Speed Sensor
Ground circuit.
Is the resistance below 5.0 ohms?
Ye s>>
Repair the (T13) Speed Sensor Ground circuit for a short to
ground.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION
TEST - VER 1. (Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PRO-
CEDURE)
No>>
Go To 7
7.CHECK THE (T14) OUTPUT SPEED SENSOR SIGNAL CIRCUIT SHORT TO VOLTAGE
Ignition on, engine not running.
With the scan tool in TIPM, actuate the TCM output.
Measure the voltage of the (T14) Output Speed Sensor Signal circuit.
Is the voltage above 0.5 volts?
Ye s>>
Repair the (T14) Output Speed Sensor Signal circuit for a
short to voltage.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION
TEST - VER 1. (Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PRO-
CEDURE)
No>>
Go To 8