P0715-INPUT SPEED SENSOR 1 CIRCUIT





For a complete wiring diagram Refer to Section 8W.

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 (DTCs P0731-36 and P1736).

2) An excessive change in input or output speeds indicating signal intermittent which will 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 signal from the input speed sensor at idle 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 when at a stop.


  • When Monitored:

    The transmission gear ratio is monitored continuously while the transmission is in gear.

  • Set Condition:

    If there is an excessive change in input RPM in any gear. This DTC can take up to five minutes of problem identification before illuminating the MIL.


Possible Causes
  
(T52) INPUT SPEED SENSOR SIGNAL CIRCUIT OPEN
  
(T13) SPEED SENSOR GROUND CIRCUIT OPEN
  
(T52) INPUT SPEED SENSOR SIGNAL CIRCUIT SHORT TO GROUND
  
(T13) SPEED SENSOR GROUND CIRCUIT SHORT TO GROUND
  
(T52) INPUT SPEED SENSOR SIGNAL CIRCUIT SHORT TO VOLTAGE
  
(T13) SPEED SENSOR GROUND CIRCUIT SHORT TO VOLTAGE
  
INPUT 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)



Diagnostic Test

1.CHECK IF DTC P0715 IS CURRENT




Is the Input Speed Sensor RPM below 400 RPM?

Yes
  • Go To 2


No
  • Go To 9

2.CHECK THE INPUT SPEED SENSOR



CAUTION: Removal of the Starter Relay will prevent the vehicle from being started in gear.


WARNING: The Starter Relay must be removed from the PDC. Failure to do so can result in personal injury or death.


NOTE: Failure to remove the Starter Relay can cause a Transmission - No Response condition.







Does the Input speed read 3000 RPM and the Output speed read 1000 RPM ± 50 RPM?

Yes


No
  • Go To 3

3.CHECK THE (T52) INPUT SPEED SENSOR SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE





NOTE: Make sure to leave the Speed Sensor, Transmission Solenoid/TRS Assembly, and Line Pressure Sensor harness connectors disconnected.


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 tool #8815 to perform diagnosis.







Is the voltage above 0.5 volts?

Yes


No
  • Go To 4

4.CHECK THE (T13) SPEED SENSOR GROUND CIRCUIT FOR A SHORT TO VOLTAGE





Is the voltage above 0.5 volts?

Yes


No
  • Go To 5

5.CHECK THE (T52) INPUT SPEED SENSOR SIGNAL CIRCUIT FOR AN OPEN







Is the resistance above 5.0 ohms?

Yes


No
  • Go To 6

6.CHECK THE (T13) SPEED SENSOR GROUND CIRCUIT FOR AN OPEN





Is the resistance above 5.0 ohms?

Yes


No
  • Go To 7

7.CHECK THE (T52) INPUT SPEED SENSOR SIGNAL CIRCUIT FOR A SHORT TO GROUND





Is the resistance below 5.0 ohms?

Yes


No
  • Go To 8

8.CHECK THE (T13) SPEED SENSOR GROUND CIRCUIT FOR A SHORT TO GROUND





Is the resistance below 5.0 ohms?

Yes


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. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)

9.CHECK WIRING AND CONNECTORS






Were there any problems found?

Yes


No
  • Test Complete.