What Does P0730 Mean?
The TCM has detected an incorrect gear ratio that does not correspond to any commanded gear. This is a general code indicating the calculated ratio from the input and output shaft speed sensors does not match the expected ratio for the gear the TCM believes is engaged. The driver may experience slipping, flaring between shifts, harsh engagements, or the transmission defaulting to limp mode.
Common Causes
30%
Worn or slipping clutch pack(s) causing the actual gear ratio to deviate from the expected ratio
25%
Low transmission fluid level or degraded fluid resulting in insufficient clutch apply pressure
20%
Faulty input or output shaft speed sensor providing inaccurate speed readings to the TCM
15%
Worn or sticking shift solenoids unable to maintain proper line pressure to clutch circuits
10%
Valve body wear or stuck valves causing incorrect hydraulic routing
Diagnostic Steps
1
Check transmission fluid level and condition — low fluid is the most common cause of ratio errors. Top off if low and check for leaks. Dark or burnt fluid indicates internal damage.
2
Monitor ISS and OSS PIDs during a road test through all gears — calculate the actual gear ratio in each gear and compare to manufacturer specifications. Identify which gear(s) have ratio deviations.
3
Check for additional gear-specific ratio codes (P0731–P0736) that will narrow down which gear is affected. The specific gear code is more diagnostic than P0730 alone.
4
Test the input and output speed sensors by comparing their readings to actual wheel speed (from ABS data) and tachometer RPM. A sensor reading off by more than 5% indicates sensor failure.
5
If a specific gear slips, perform a line pressure test in that gear range. Low pressure indicates a hydraulic issue (solenoid or valve body); normal pressure with slipping indicates worn clutch packs.
6
Inspect the solenoids for proper operation — measure resistance and current draw, and command on/off via the scan tool.
Estimated Repair Cost
$150 - $4,000
Parts + labor, varies by vehicle and location
The TCM has detected an incorrect gear ratio that does not correspond to any commanded gear. This is a general code indicating the calculated ratio from the input and output shaft speed sensors does not match the expected ratio for the gear the TCM believes is engaged. The driver may experience slip...
The most common cause of P0730 (Engine Speed Input Circuit Intermittent) is: Worn or slipping clutch pack(s) causing the actual gear ratio to deviate from the expected ratio
Typical repair costs for P0730 range from $150 to $4,000, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Incorrect gear ratios indicate slippage or sensor errors that can worsen over time. Driving with a slipping transmission generates excessive heat that can cause catastrophic failure. Limit driving to short, low-speed trips to a repair facility. Avoid heavy loads and aggressive driving.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0730 to identify the root cause.
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Quick Info
Category
Powertrain
System
Automatic Transmission / Gear Ratio Control
Difficulty
Type
Generic (SAE)
Recommended Tools
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