For a complete wiring diagram Refer to Section 8WThe 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 and P1736).2) An excessive change in input or output speeds indicating signal intermittent may result in the DTCs P0716 and/or P0721 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.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 MILPossible CausesLOW FLUID LEVELCUT L/R TOWER SEAL ON MAIN VALVE BODYCUT L/R CLUTCH PISTON SEALSBROKEN OR MISSING L/R CLUTCH BLEED ORIFICE (IN L/R CLUTCH RETAINER)CUT L/R ACCUMULATOR PISTON SEAL IN MAIN VALVE BODYCRACKED L/R ACCUMULATOR PISTON IN MAIN VALVE BODYCUT OD/REV PISTON SEALSBROKEN OR MISSING OD/REV BLEED ORIFICE (IN OD/REV CLUTCH PISTON)BROKEN REVERSE CARRIER HUB WELDBROKEN REVERSE SUN GEAR WELD TO THE REACTION CARRIERAlways perform the 45RFE/545RFE Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE) 1. CHECK FOR RELATED DTCSWith the scan tool, check for other transmission DTC'sAre there any Transmission; solenoid, line pressure, speed sensor, and/or loss of prime DTC's present?YesRefer to appropriate symptom in the Transmission category. Perform the test for P0944-LOSS OF PRIME first if it is present.NoGo To 22. CHECK IF DTC IS CURRENTWith the scan tool, perform the Reverse Gear Clutch test. Follow the instructions on the scan tool.Increase the throttle angle, TPS degree, to 30°, for no more than a few seconds.Do not overheat the transmission.Make sure to record all DTC EVENT DATA stored in the scan tool for future reference in this test procedure.Did the clutch test pass, input speed remain at zero?YesGo To 3NoGo To 43. CHECK DTC EVENT DATAThe conditions necessary to set this DTC are not currently present.With the scan tool, check the DTC EVENT DATA to help identify the conditions in which the DTC was set.Does the DTC EVENT DATA show an input speed reading of zero?YesGo To 8NoGo To 44. POSSIBLE INTERNAL TRANSMISSION CAUSESRemove the Transmission Oil Pan and Valve Body and check the following per the Service Information:Clutch or metal debris in the panL/R clutch tower seal on the main valve body or cuts and the L/R accumulator piston and seals.Air check the Reverse and L/R Hydraulic Clutch circuits (in the case) for excessive air leakage.Both Hydraulic Clutch circuits contain a small bleed orifice , a small amount of air leakage is normal. The Reverse hydraulic clutch circuit bleed orifice connects to the OD hydraulic clutch cavity. A small amount of air leakage into the OD hydraulic clutch circuit is considered normal.Were there any problems found?YesRepair as necessary. If clutch debris is present, remove the transmission and inspect the Reverse and L/R clutches, and inspect the Transmission Oil Pump and Main Regulator Valve for damage or sticking in its bore.Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE) NoGo To 55. CLUTCH TEST FAILUREDid the clutch test fail in reverse?YesGo To 6NoTest complete.Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE) 6. CHECK FOR BROKEN REVERSE SUN GEAR WELDWorking through the windows in the bottom of the case, check for a broken Reverse Sun gear weld to the reaction carrier as follows:1) Hold the Transmission Output Shaft by holding the Transmission Manual Lever in the park position.2) Rotate the Input Annulus gear and drive shell, (the drum that encloses the two rearmost carriers).3) Check to see if the reaction carrier (the front-most carrier, whose outer shell is splined to the 2C clutch) is rotating faster than the drive shell is being turned.Is the reaction carrier turning faster than the drive shell?YesGo To 7NoReplace the reaction carrier per the Service Information.Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE) 7. CHECK REVERSE CARRIER HUBRemove the Transmission per the Service Information and inspect the weld on the reverse carrier hub.Were there any problems found?YesRepair as necessary. Refer to the Service Information for proper repair procedures.Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE) NoDisassemble and inspect the input clutch assembly. Check the Reverse clutch reaction plate snap ring. Check the OD and Reverse clutch seals, discs, and bleed orifice (in the OD/Reverse clutch piston). Check the Reverse hub and shaft. Repair as necessary. Refer to the Service Information for proper repair procedures.Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE) 8. CHECK FOR INTERMITTENT OPERATIONIntermittent gear ratio DTCs can be set by problems in the Input and Output Speed Sensor circuits and/or Speed Sensor Ground circuit.Remove the Starter Relay.Removal of the Starter Relay will prevent the vehicle from being started in gear. The Starter Relay must be removed from the PDC. Failure to do so can result in personal injury or death.Failure to remove the Starter Relay can cause a Transmission - No Response condition.Check the Speed Sensor wiring and connectors for good connection, then perform a wiggle test using the Transmission Simulator, Miller tool #8333.Were there any problems found?YesRepair as necessary.Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE) NoTest complete.