Improper Ratio

(P0730) IMPROPER RATIO





When Monitored and Set Condition
- 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 >300 RPM or calculated transmission ratio is above threshold. During an Upshift - detected (calculated) gear is less than actual (expected) gear-1. During Downshift - detected (calculated) gear is less than actual (expected) gear.

POSSIBLE CAUSES
- INTERNAL TRANSMISSION
- TRANSMISSION CONTROL MODULE

Diagnostic Test
1. PRE-DIAGNOSTIC CHECK OUT





Note: Low fluid level can be the cause of many transmission problems. If the fluid level is low, locate and repair the leak then check and adjust the fluid level in accordance with the Service Information.

Note: Always perform diagnostics with a fully charged battery to avoid false symptoms.
With the DRB III*, read the engine DTCs. Check and repair all engine DTCs prior to performing transmission symptom diagnostics.
With the DRB III*, read and record all Transmission DTCs.

Note: Check connectors - Clean/repair as necessary. Poor pin to terminal connections can set DTCs.
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors. Repair as necessary.
Most DTCs set on start up but some must be set by driving the vehicle such that all diagnostic monitors have run.

Note: Verify flash level of transmission controller. Some problems are corrected by software upgrades to the transmission controller.

Note: Check for any Technical Service Bulletins that may apply.

Perform this procedure prior to Symptom diagnosis.
Continue
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2. TRANSMISSION MECHANICAL PROBLEM
Determine if there are any Transmission Mechanical problems present. Remove the Transmission Oil Pan and inspect for debris or a plugged Transmission Oil Filter.
Refer to the Service Information for proper removal and inspection procedures.
Is there any debris, plugged Transmission Oil Filter, or signs of an internal transmission problem?
Yes>>Refer to the Transmission - Service Information for the proper repair procedure. Pay particular attention to the valve body components and stuck solenoids.
Perform NAG1 TRANSMISSION VERIFICATION TEST. Verification Tests
No>>Replace the Transmission Control Module.
Perform NAG1 TRANSMISSION VERIFICATION TEST.