P0730 on Mercedes-Benz
Incorrect Gear Ratio
P0730 on Mercedes-Benz vehicles indicates incorrect gear ratio. Au7o has documented this code across 3 Mercedes-Benz models — most commonly on CLS-Class, GLS, Metris. This code means the transmission computer detected that the actual gear ratio (calculated from input vs. output shaft speeds) does not match what it should be for the commanded gear. In other words, the transmission isn't delivering the correct gear, which often shows up as slipping, flaring RPM during shifts, or being stuck in the wrong gear. It can stem from internal mechanical wear, low or contaminated fluid, or faulty solenoids and sensors. The vehicle may shift harshly or enter limp mode. Typical repair costs on Mercedes-Benz range from $150 to $4,000, depending on the specific model and root cause.
Common Causes of P0730
- •Low or contaminated transmission fluid
- •Worn clutches or bands (internal slipping)
- •Faulty shift solenoids
- •Dirty or sticking valve body
- •Faulty input or output speed sensor
- •Internal hydraulic/line pressure problems
- •Torque converter problems
- •General high-mileage transmission wear
P0730 on Mercedes-Benz by Model
Mercedes-Benz CLS-Class(1 issue)
- 7G-Tronic Transmission Valve Body Failure2005-2014
The 722.9 7G-Tronic automatic transmission in CLS models suffers from valve body conductor plate failures. The electronic conductor plate controls shift solenoids and develops internal short circuits or loses communication, causing harsh shifting, getting stuck in limp mode, or refusing to shift out of park. This is one of the most common transmission failures on Mercedes vehicles of this era.
Mercedes-Benz GLS(1 issue)
- 9G-Tronic Harsh Shift2017-2023
The 9G-Tronic nine-speed automatic exhibits harsh low-speed shifts and hunting between gears on inclines. The transmission software struggles to select the optimal gear among nine ratios, particularly noticeable in stop-and-go traffic.
Mercedes-Benz Metris(1 issue)
- Harsh Shifting and Delayed Engagement in 7G-Tronic Transmission2016-2023
The 7G-Tronic automatic transmission in the Metris exhibits harsh shifts, particularly the 2-3 and 4-5 upshifts, along with delayed engagement when shifting from park to drive. The issue worsens as the transmission fluid ages and the valve body accumulates debris from clutch material.
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View P0730 across all makes →Frequently Asked Questions
What does P0730 mean on Mercedes-Benz?▼
P0730 stands for "Incorrect Gear Ratio." This code means the transmission computer detected that the actual gear ratio (calculated from input vs. output shaft speeds) does not match what it should be for the commanded gear. In other words, the transmission isn't delivering the correct gear, which often shows up as slipping, flaring RPM during shifts, or being stuck in the wrong gear. It can stem from internal mechanical wear, low or contaminated fluid, or faulty solenoids and sensors. The vehicle may shift harshly or enter limp mode. On Mercedes-Benz specifically, this code is documented across 3 models.
What causes P0730 on Mercedes-Benz vehicles?▼
Common causes on Mercedes-Benz: Low or contaminated transmission fluid, Worn clutches or bands (internal slipping), Faulty shift solenoids, Dirty or sticking valve body, Faulty input or output speed sensor. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0730 on a Mercedes-Benz?▼
Repair costs on Mercedes-Benz range from $150 to $4,000, depending on the specific model and root cause.
Which Mercedes-Benz models have P0730 documented?▼
Au7o has documented P0730 on 3 Mercedes-Benz models: CLS-Class, GLS, Metris.