P0733-GEAR RATIO ERROR IN 3RD

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) 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.


  • 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
 
RELATED DTCS PRESENT
 
INPUT SPEED SENSOR OR WIRING
 
LOW FLUID LEVEL
 
CRACKED OR MIS-INSTALLED PRIMARY OIL FILTER OR SEAL
 
BENT OR BROKEN ACCUMULATOR COVER ON MAIN VALVE BODY
 
WORN SOLENOID SWITCH VALVE OR PLUGS
 
STUCK OR STICKING MAIN REGULATOR VALVE
 
BURNED UD OR OD CLUTCH
 
CUT OD OR UD PISTON SEAL
 
BROKEN OR MISSING UD OR OD BLEED ORIFICE IN MAIN VALVE BODY
 
BROKEN OR MISSING BLEED ORIFICE IN UD OR OD CLUTCH PISTON
 
CUT OD OR UD ACCUMULATOR PISTON SEAL
 
CRACKED OD OR UD ACCUMULATOR PISTON
 
CUT OR MISSING #6 CHECK BALL
 
TRANSMISSION SOLENOID/TRS ASSEMBLY
 
BROKEN WELD - REVERSE CARRIER HUB TO CARRIER
 
BROKEN REACTION SHAFT SUPPORT SEAL RING
 
POOR MACHINING ON PUMP VALVE BODY FACE
 


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 RELATED DTCS ARE PRESENT



Are there any Transmission; solenoid, line pressure, speed sensor, and/or loss of prime DTCs present?

Yes
  • Refer to appropriate symptom in the Transmission category. Perform the test for P0944-LOSS OF PRIME first if it is present.


No
  • Go To 2

2.CHECK DTC EVENT DATA


NOTE: 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 P0733?

Yes
  • Go To 4


No
  • Go To 3

3.CHECK THE TARGET GEAR IN DTC EVENT DATA



Does the DTC EVENT DATA display information for the DTC P1790, with target gear = 3rd, or with both OD and UD clutches applying?

Yes
  • Go To 4


No
  • Go To 7

4.CHECK INPUT RPM IN DTC EVENT DATA



Does the Input RPM read zero?

Yes
  • Check the input speed sensor and wiring. Refer to test P0715 and diagnose as if the DTC is current.


No
  • Go To 5

5.CHECK LINE PRESSURE READING



Is the line pressure reading more than 10 psi below the desired line pressure?

Yes
  • Go To 6


No
  • Go To 7

6.CHECK TRANSMISSION OIL FILTER




NOTE: Make sure the Primary Transmission Oil Filter and seal are properly installed and are not cracked or split.



Does the Oil Pan contain excessive debris and/or is the Primary Oil Filter cracked, plugged or mis-installed?

Yes


No

7.CHECK IF DTC P0733 IS CURRENT



CAUTION: Do not overheat the transmission.


NOTE: If the OD clutch is faulty, the overrunning clutch will hold and the slip test will pass. The 3rd gear clutch test will not detect a faulty OD clutch. However, it will detect a faulty UD clutch.



Did the clutch test pass, did the Input Speed remain at zero?

Yes
  • Go To 8


No

8.CHECK FOR INTERMITTENT OPERATION





Were there any problems found?

Yes


No
  • Go To 9

9.CHECK FOR SLIPPAGE




Is there an obvious slippage noticed in 3rd gear, or runaway on the 2-3 shift?

Yes


No

10.CHECK THE UD HYDRAULIC CLUTCH CIRCUIT



NOTE: The UD clutch passage contains a small bleed orifice, a small amount of air leakage is normal.



Were there any problems found, excessive debris and/or excessive air leakage in the UD hydraulic clutch circuit?

Yes


No

11.CHECK UD ACCUMULATOR PISTON



Were there any problems found?

Yes
  • Repair as necessary. Refer to the Service Information for proper repair procedures.


No

12.CHECK FOR EXCESSIVE DEBRIS




NOTE: The OD clutch passage contains a small bleed orifice which connects to the Reverse clutch hydraulic circuit, a small amount of air leakage into the Reverse clutch passage is normal.



Were there any problems found, excessive debris, and/or excessive air leakage in the OD hydraulic clutch circuit?

Yes


No

13.CHECK THE OD ACCUMULATOR





Were there any problems found?

Yes


No

14.CHECK FOR NO REVERSE


During the road test on a previous test, did the vehicle have no reverse and no 3rd gear, but 1st and 2nd gears were OK?

Yes


No

15.CHECK FOR BROKEN REVERSE CARRIER WELD



Were there any problems found?

Yes
  • Repair as necessary.


No

16.CHECK IF DTC RESETS


Did the DTC P0733 reset during the road test?

Yes


No

17.LIST OF POSSIBLE CAUSES



  • Excessive debris in the Transmission Oil pan, plugged, cracked, or mis-installed Primary Transmission Oil Filter and/or seal.
  • Cut or missing #6 check ball in the main valve body.
  • OD and UD accumulator pistons and seals and bleed orifices, and the Solenoid Switch Valve and Plugs in the main valve body.
  • OD and UD clutch piston seals, reaction shaft support seal rings and dribbler assemblies, and the flatness of the pump valve body and pump housing faces.
  • Main regulator valve for sticking in its bore.


View repair

Repair

18.CHECK FOR INTERMITTENT OPERATION


  • If the DTC Event Data shows fault P0733 was set in the Park, Reverse, or Neutral, replace the Powertrain Control Module.
  • If the DTC Event Data shows fault P0733 set with input RPM = zero, check the input speed sensor and related wiring.
  • If the DTC Event Data shows fault P0733 set with line pressure significantly below desired line pressure, check for the cause of low line pressure (i.e., oil level, misinstalled or damaged primary filter or filter seal, sticking main regulator valve in pump, etc.).
  • If the DTC Event Data shows fault P0733 set with the OD or UD pressure switch open (but line pressure matches Desired Line Pressure), air check the OD and UD hydraulic clutch circuits for leakage per the Service Information. If the OD and UD hydraulic clutch circuits are OK, replace the Transmission Solenoid/TRS assembly.




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.







Were there any problems found.

Yes


No
  • Test Complete.