P0735

P0735-GEAR RATIO ERROR IN 5TH

For a complete wiring diagram, refer to: Electrical Diagrams

Theory of Operation
The Transmission Control Module (TCM) constantly calculates the transmission ratio based on the input speed sensor 1 and 2 (N2-N3) signals and the calculated output shaft speed. The intent of this diagnostic is to detect if the transmission is slipping or an invalid gear ratio is present.

When Monitored
Engine RPM greater than 450 RPM, output speed greater than 180 RPM, no N2 - N3 input speed sensor errors present, no gear selector lever errors present, no ABS system errors, and all wheel speeds above 450 RPM.

Set Condition
No shifting operation and detected gear is not the actual gear. No shifting operation - detected (calculated) gear is less than actual (expected) gear, no plausible gear is calculated, actual turbine speed - calculated turbine speed is greater than 300 RPM or calculated transmission ratio is above threshold. During an Upshift -detected (calculated) gear is less than actual (expected) gear. During Downshift - detected (calculated) gear is less than actual (expected) gear.

Possible Causes
- LOW TRANSMISSION FLUID
- OTHER TRANSMISSION DTCS PRESENT
- INTERNAL TRANSMISSION FAILURE

Always perform the NAG1 Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test
1. CHECK FOR OTHER TRANSMISSION DTCS
With the scan tool, check transmission DTCS

Are there any solenoid and/or solenoid supply voltage DTCs present?
Yes >> Refer to - AUTOMATIC TRANSMISSION - AUTOMATIC TRANSMISSION NAG1 - ELECTRICAL DIAGNOSTICS category and perform the appropriate symptom.
No >> Go To 2
2. CHECK TRANSMISSION FLUID LEVEL
Check the transmission fluid level per the Service Information. Refer to - AUTOMATIC TRANSMISSION-AUTOMATIC TRANSMISSION NAG1/SERVICE INFORMATION for the appropriate service procedure.

Is the fluid level correct?
Yes >> Go To 3
No >> Properly adjust the fluid level per the Service Information. Refer to - AUTOMATIC TRANSMISSION - AUTOMATIC TRANSMISSION NAG1/SERVICE INFORMATION for the appropriate service procedure.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1. Verification Tests
3. CHECK IF DTC IS CURRENT
With the scan tool, record the Environmental Data and erase Transmission DTCs.

NOTE: If the TCM detects and stores a DTC, the TCM also stores the vehicles operating conditions under which the DTC originally set and is located in scan tool under Environmental Data. Before erasing any stored DTCs, record any available data to assist in duplicating the conditions in which the DTC originally set.

Using the Environmental Data recorded earlier, test drive the vehicle while trying to duplicate the conditions in which the DTC originally set.

Did the DTC P0735-GEAR RATIO ERROR IN 5TH reset?
Yes >> Repair internal transmission as necessary. Pay particular attention to components related to referenced DTC. Refer to - AUTOMATIC TRANSMISSION-AUTOMATIC TRANSMISSION NAG1/SERVICE INFORMATION for the appropriate service procedures.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1. Verification Tests
No >> Go To 4
4. INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.
Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
Wiggle the wiring and connectors while checking for any possible open or shorted circuits.
Check for any Service Information Tune-ups or Technical Service Bulletins that may apply.

Were there any problems found?
Yes >> Repair as necessary.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1. Verification Tests
No >> Test Complete.