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 P01736). 2) An excessive change in input or output speeds indicating signal intermittent will 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 MIL.Possible CausesLOW FLUID LEVELINPUT SPEED SENSOR OR WIRINGVALVE BODY ACCUMULATOR COVER FAILEDCUT OD OR 4C ACCUMULATOR SEALCRACKED OD OR 4C ACCUMULATOR PISTONBROKEN OR MISSING OD BLEED ORIFICE IN MAIN VALVE BODYCUT 4C TOWER SEALTRANSMISSION SOLENOID/TRS ASSEMBLYCUT OR MISSING #5 OR #6 CHECK BALLWORN SOLENOID SWITCH VALVE OR PLUGSCUT OD OR 4C PISTON SEALSTUCK MAIN REGULATOR VALVEBURNED OD OR 4C CLUTCHBROKEN OR MISSING 4C BLEED ORIFICE IN 2C/4C RETAINERBROKEN REACTION SHAFT SUPPORT SEAL RINGPOOR MACHINING ON PUMP VALVE BODY FACELOOSE / MISSING DRIBBLER ORIFICE ASSEMBLY IN REACTION SHAFT SUPPORTCRACKED / LOOSE / MISSING OD/REVERSE PISTON BLEED ORIFICEBROKEN REVERSE CARRIER HUB WELDBROKEN REVERSE SUN GEAR WELD TO 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 DTCsIf any of these DTCs are present, perform their respective tests first.Are there any Transmission solenoid, line pressure, speed sensor, and/or loss of prime DTCs present?YesRefer to the Transmission category and perform the appropriate symptom. If any of these DTCs are present, they may cause a Speed Ratio Error. Perform the test for P0944 first if it is present.NoGo To 22. CHECK DTC EVENT DATAWith the scan tool, read and record the DTC EVENT DATA.Make sure to record all DTC EVENT DATA stored in the scan tool for future reference in this test procedure.Does the DTC EVENT DATA display information for the DTC P0734?YesGo To 4NoGo To 33. CHECK FOR ANOTHER DTCIn the DTC EVENT DATA recorded earlier, does the DTC EVENT DATA show the DTC P1790, with Target Gear = 4th, or with both the 4C and OD clutches applying?YesGo To 4NoGo To 64. CHECK INPUT RPMIn the DTC EVENT DATA recorded earlier, does the Input rpm read zero?YesRefer to the Transmission category and perform the diagnostic procedure for P0715 (Input Speed Sensor Error). Diagnose the DTC as if it is set and current.NoGo To 55. CHECK LINE PRESSURE READINGIn the DTC EVENT DATA recorded earlier, is the line pressure reading more than 10 PSI below the desired line pressure reading?YesRemove the Transmission Oil pan and check the Transmission Oil filter for improper installation or plugged, if Primary oil filter is OK, check the main regulator valve in pump. If excessive debris is in the oil pan, check clutches and 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) NoGo To 66. CHECK TRANSMISSION FOR SLIPPAGEErase DTCs and road test the vehicle.Check the transmission operation in reverse and all forward gears.During the road test, was there any obvious slippage noted in 4th gear or a runaway during the 3-4 shift?YesGo To 8NoGo To 77. CHECK IF DTC RESETSWith the scan tool, check for Transmission DTCs after the road test.Did the DTC P0734 reset?YesGo To 8NoTest Complete.8. CHECK INTERNAL TRANSMISSIONRemove the Transmission Oil Pan and Valve Body per the Service Information and check for the following:Excessive debris in the oil pan.Remove the Valve Body and check if the accumulator cover is intact and the 4C tower seal is not cut or split.OD and 4C accumulator pistons for cracks and/or cut seals. Solenoid Switch Valve and its plugs for stickiness or wear.Cut or missing #5 and/or #6 check ball.OD bleed orifice on top of the Valve BodyAir check the OD and 4C hydraulic clutch circuits for excessive leakage. Refer to the Service information.Both the OD and 4C hydraulic clutch circuits contain a small bleed orifice. A small amount of air leakage is considered normal. The OD hydraulic clutch circuit bleed orifice connects to the Reverse input clutch hydraulic cavity. A small amount of air leakage into the Reverse hydraulic clutch circuit is considered normal.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) NoGo To 99. CHECK REVERSE GEARWas there no reverse gear during the road test?Yes (no reverse)Go To 10No (reverse gear OK)Replace Transmission Solenoid/TRS Assembly per the Service Information. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE/TRANS SOLENOID/TRS ASSY - REMOVAL) Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE) 10. CHECK ROAD TEST RESULTSDuring the road test, was there no 2nd gear and no 4th gear, but 3rd gear (limp-in) was OK?YesGo To 11NoGo To 1211. 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?YesReplace Transmission Solenoid/TRS Assembly per the Service Information. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE/TRANS SOLENOID/TRS ASSY - REMOVAL) Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE) NoReplace the reaction carrier per the Service Information.Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE) 12. CHECK REVERSE CARRIER HUB WELDRemove 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 OD and Reverse clutch seals, discs, and bleed orifice (in the OD/Reverse clutch piston). Check the OD 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)