Applicable Systems
OBD-II
Symptoms
Transmission actual gear ratio doesn't match commanded ratio; internal clutch slip or mechanical failure suspected.
Possible Causes
- Internal clutch slippage
- Solenoid not applying clutch correctly
- Low fluid or burnt fluid
- Internal mechanical damage
Troubleshooting Steps
- Step 1: Check transmission fluid level and condition
Fluid at correct level, red/clean - Step 2: Check for other transmission codes first
Repair other codes first - Step 3: Compare input vs output speed for each gear
Ratio matches commanded gear - Step 4: If ratio off, internal transmission issue
Transmission internal inspection needed - Step 5: Rebuild or replace transmission if internal damage
Ratios correct after repair
How to Reset
Clear with OBD-II scanner after transmission repair.
Common Replacement Parts
- Transmission rebuild kit or remanufactured unit
Frequently Asked Questions
- Q: Can low fluid cause P0730?
Yes. Low fluid reduces line pressure, causing clutch slippage. Always check fluid level and condition before condemning transmission.
Source: SAE J2012 standard DTC list + OBD-II portal
Category: OBD-II