P0733 on Mercedes-Benz
Gear 4 Incorrect Ratio
P0733 on Mercedes-Benz vehicles indicates gear 4 incorrect ratio. Au7o has documented this code across 1 Mercedes-Benz model — most commonly on C-Class. This code indicates the transmission control module found that the actual gear ratio in 4th gear is outside the acceptable range for that gear. It is detected by comparing transmission input speed against output speed while 4th gear is engaged. A mismatch typically signals the transmission is slipping in 4th gear or that a control/hydraulic fault is preventing proper engagement. Typical repair costs on Mercedes-Benz range from $600 to $1,800, depending on the specific model and root cause.
Common Causes of P0733
- •Low or contaminated transmission fluid
- •Worn 4th-gear clutch packs or bands
- •Failing shift solenoid for 4th gear
- •Valve body or line pressure issues
- •Internal transmission mechanical wear
- •Restricted transmission filter
- •Faulty input or output speed sensor
P0733 on Mercedes-Benz by Model
Mercedes-Benz C-Class(1 issue)
- 722.6 5G-Tronic conductor plate failure (limp mode, stuck in 2nd gear)1996-2002
The 722.6 five-speed automatic (fitted to W202 facelift cars from ~1996 onward and all 2001-2002 W203s) uses an electronic conductor plate mounted on top of the valve body that integrates the speed sensors and routes signals to the solenoids. The plate fails for two reasons: (1) the internal RPM sensors get coated by ferrous wear particles when the fluid is never changed, producing implausible-slip codes, and (2) the soldered traces and embedded capacitor crack from heat cycling. Failure puts the transmission into limp-home mode — stuck in 2nd gear, harsh 1-2 and 2-3 shifts, or no upshift at all. Often accompanied by codes P0717, P0720, P0731-P0736 and a transmission warning light. This is the single most common 722.6 failure across every Mercedes chassis that uses it.
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What does P0733 mean on Mercedes-Benz?▼
P0733 stands for "Gear 4 Incorrect Ratio." This code indicates the transmission control module found that the actual gear ratio in 4th gear is outside the acceptable range for that gear. It is detected by comparing transmission input speed against output speed while 4th gear is engaged. A mismatch typically signals the transmission is slipping in 4th gear or that a control/hydraulic fault is preventing proper engagement. On Mercedes-Benz specifically, this code is documented across 1 model.
What causes P0733 on Mercedes-Benz vehicles?▼
Common causes on Mercedes-Benz: Low or contaminated transmission fluid, Worn 4th-gear clutch packs or bands, Failing shift solenoid for 4th gear, Valve body or line pressure issues, Internal transmission mechanical wear. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0733 on a Mercedes-Benz?▼
Repair costs on Mercedes-Benz range from $600 to $1,800, depending on the specific model and root cause.
Which Mercedes-Benz models have P0733 documented?▼
Au7o has documented P0733 on 1 Mercedes-Benz model: C-Class.