Gear Ratio Incorrect (5th Gear)
The transmission control module detected an error in the 5th gear ratio.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
This code means the transmission isn't shifting into 5th gear properly, which can cause shifting problems and affect performance.
What the computer is actually seeing
The transmission control module (TCM) expects to see a specific input speed relative to the output speed while in 5th gear. If the ratio is off—typically more than 10% of what's expected—this code sets.
What a healthy reading looks like
Input speed should match output speed ratio within 10%; for example, if the input speed is 2000 RPM, the expected output should be around 1500 RPM for correct operation.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Check the transmission fluid level; it should be between the 'full' marks as per manufacturer's specs.
- 22. Inspect the wiring and connectors leading to the input and output speed sensors for damage or corrosion; repair as needed.
- 33. Use a scan tool to monitor input and output speeds; confirm they stay within 10% of each other when in 5th gear.
- 44. If there’s a significant discrepancy, inspect or replace the input/output speed sensors only if they are confirmed faulty.
- 55. Check the transmission valve body and solenoids for any signs of sticking or blockage; repair or replace as necessary.
Common causes
- Faulty transmission fluid level
- Damaged sensor or wiring
- Problems with valve body or solenoids
- Worn transmission components
- Poor electrical connections
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's moderate severity; driving may be okay, but you'll likely notice poor performance and shifting issues. Fix soon.
Will this code come back after I clear it?
If the underlying issue isn’t addressed, yes, it will return.
Why does this code appear with P0730?
P0730 indicates a general gear ratio problem; P0735 specifies the issue is with 5th gear specifically.
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