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 and P1736).
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.
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When Monitored:
Continuously with the ignition on, engine running, with the transmission in gear.
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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
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RELATED DTCS PRESENT
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INPUT SPEED SENSOR OR WIRING
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LOW FLUID LEVEL
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CRACKED OR MIS-INSTALLED PRIMARY OIL FILTER OR SEAL
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BENT OR BROKEN ACCUMULATOR COVER ON MAIN VALVE BODY
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WORN SOLENOID SWITCH VALVE OR PLUGS
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STUCK OR STICKING MAIN REGULATOR VALVE
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BURNED UD OR OD CLUTCH
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CUT OD OR UD PISTON SEAL
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BROKEN OR MISSING UD OR OD BLEED ORIFICE IN MAIN VALVE BODY
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BROKEN OR MISSING BLEED ORIFICE IN UD OR OD CLUTCH PISTON
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CUT OD OR UD ACCUMULATOR PISTON SEAL
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CRACKED OD OR UD ACCUMULATOR PISTON
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CUT OR MISSING #6 CHECK BALL
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TRANSMISSION SOLENOID/TRS ASSEMBLY
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BROKEN WELD - REVERSE CARRIER HUB TO CARRIER
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BROKEN REACTION SHAFT SUPPORT SEAL RING
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POOR MACHINING ON PUMP VALVE BODY FACE
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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
With the scan tool, check for other transmission DTCs
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
2.
CHECK DTC EVENT DATA
With the scan tool, read and record the 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
No
3.
CHECK THE TARGET GEAR IN DTC EVENT DATA
In the DTC EVENT DATA, identify the DTC that was recorded earlier.
Does the DTC EVENT DATA display information for the DTC P1790, with target gear = 3rd, or with both OD and UD clutches applying?
Yes
No
4.
CHECK INPUT RPM IN DTC EVENT DATA
Refer to the DTC EVENT DATA recorded earlier.
Does the Input rpm read zero?
Yes
-
Check the input speed sensor and wiring. Refer to test P0716 and diagnose as if the DTC is current.
No
5.
CHECK LINE PRESSURE READING
Refer to the DTC EVENT DATA recorded earlier.
Is the line pressure reading more than 10 psi below the desired line pressure?
Yes
No
6.
CHECK TRANSMISSION OIL FILTER
Turn the ignition off to the lock position.
Remove and inspect the Transmission Oil Pan for excessive debris per the Service Information.
Remove and inspect the Primary Oil Filter per the Service Information.
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
With the scan tool, perform the 3rd Gear Clutch Test. Follow the instructions on the scan tool.
Increase the throttle angle, TPS Degree, to 30 degrees for no more than a few seconds.
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
No
8.
CHECK FOR INTERMITTENT OPERATION
Check the Shifter adjustment per the Service Information.
Intermittent gear ratio DTCs can be set by problems in the Input and Output Speed Sensor circuits and/or Speed Sensor Ground circuit.
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 started in gear.
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.
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?
Yes
No
9.
CHECK FOR SLIPPAGE
With the scan tool, erase Transmission DTCs.
Road test the vehicle. Check operation in 3rd gear, 4th gear, and Reverse.
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
Remove Transmission Oil Pan and check for excessive debris.
Remove the Valve Body and air check the UD hydraulic clutch circuit (in the case) per the Service Information.
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
Check the UD bleed orifice, accumulator piston, and accumulator piston seal in the main valve body.
Were there any problems found?
Yes
-
Repair as necessary. Refer to the Service Information for proper repair procedures.
No
12.
CHECK FOR EXCESSIVE DEBRIS
Remove the Transmission Oil Pan and check for excessive debris.
Remove the valve body and check if the accumulator cover is intact.
Air check the OD hydraulic clutch circuit (in the case) per the Service Information.
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
Check the OD Accumulator piston for cracks or a cut seal.
Check for a cut or missing #6 check ball.
Check the Solenoid Switch Valve and its plugs for sticking in its bore or excessive wear.
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
Remove the Transmission per the Service Information and inspect the weld on the reverse carrier hub.
Were there any problems found?
Yes
No
16.
CHECK IF DTC RESETS
Did the DTC P0733 reset during the road test?
Yes
No
17.
LIST OF POSSIBLE CAUSES
If any other DTCs set during the road test, refer to the appropriate symptom in the Transmission category.
If no other DTCs set during the road test, below is a list of possible causes, but not strictly limited to those.
Check for:
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Excessive debris in the Transmission Oil pan, plugged, cracked, or mis-installed Primary Transmission Oil Filter and/or seal.
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Cut or missing #6 check ball in the main valve body.
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OD and UD accumulator pistons and seals and bleed orifices, and the Solenoid Switch Valve and Plugs in the main valve body.
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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
The conditions 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.
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If the DTC Event Data shows fault P0733 was set in the Park, Reverse, or Neutral, replace the Powertrain Control Module.
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If the DTC Event Data shows fault P0733 set with input rpm = zero, check the input speed sensor and related wiring.
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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.
Check the gearshift linkage adjustment.
Intermittent Gear Ratio DTCs can be set by problems in the Input and Output Speed Sensor circuits and/or Speed Sensor Ground circuit.
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 started in gear.
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.
Wiggle wiring and connectors while checking for intermittent operation with the Transmission Simulator.
Gear ratio DTCs can also be set under extreme temperature conditions.
Verify if the problem is only experienced under extreme hot or cold conditions.
Were there any problems found.
Yes
No