P0717 on Mercedes-Benz: How to Diagnose & Fix
Input/Turbine Speed Sensor Circuit No Signal
4 Mercedes-Benz models · 4 documented issues · 4 critical · $300-$2,200 repair
P0717 on Mercedes-Benz by model: symptoms, diagnosis and fix
The 722.9 7G-Tronic transmission conductor plate (internal electrical board with speed sensors) fails, causing limp mode, harsh shifting, and loss of gears. The electrical connector corrodes or the sensors crack from heat cycling.
Common Symptoms
- Transmission goes into limp mode (stuck in one gear)
- Harsh shifting between gears
How to Fix
Replace the conductor plate and both speed sensors inside the transmission. Requires dropping the transmission pan and valve body. Replace the transmission filter and fluid at the same time.
Owner tips & cautions
- TipThe conductor plate is a $150 part and 3-hour DIY job. Many shops quote $1,500+ because they don't differentiate it from a full valve body replacement.
Sources for this issue (4)
- ECU Testing: Mercedes 7G-Tronic TCM conductor plate failuremanufacturer
- MB Medic: 722.9 7G-Tronic Valve Body & Conductor Plate Must Readmedia
- UpFix: 722.9 Transmission Conductor Plate Repair Could Save $1000smanufacturer
- The Autopian: Heres What A Conductor Plate Is And Why It Kills So Many Mercedes Vehiclesmedia
The electronic conductor plate integrated into the 722.9 7-speed automatic's valve body (which houses the internal TCM, speed sensors and shift solenoids) is a widely reported failure on R171 SLKs equipped with the 7G-Tronic. As the plate's internal speed sensors and soldered joints degrade with heat cycling, the transmission drops into limp mode, typically locking into a single forward gear (often 2nd). The condition is temperature-sensitive and commonly appears from roughly 50,000-90,000 miles.
Common Symptoms
- Transmission stuck in gear (often 2nd), won't shift up
- Limp mode / reduced speed limited to ~40 mph
- Harsh or delayed shifts, especially when cold
- Intermittent faults that come and go with temperature
- Speed-sensor fault codes
How to Fix
Replace or rebuild the conductor plate (the revised design), refresh the valve body, and perform a transmission fluid and filter service plus an adaptation reset. Independent specialists offer a cheaper conductor-plate reman as an alternative to Mercedes' full valve-body replacement (roughly $2,000-$3,000 at a dealer). A neglected fluid service accelerates the failure, so periodic 722.9 fluid changes are recommended.
Sources for this issue (3)
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.
Common Symptoms
- Transmission stuck in 2nd gear (limp-home mode)
- Harsh or delayed 1-2 and 2-3 shifts
- No upshift past 2nd
- Transmission warning light or wrench icon
- Speedometer drops to 0 intermittently while driving
- Fluid on the 13-pin transmission electrical connector
How to Fix
Replace the conductor plate (Mercedes p/n A140 270 13 61 or supersession). The 722.6 conductor plate is plug-and-play with no coding required (unlike the later 722.9). Always replace the 13-pin pilot bushing/connector adapter at the same time — ATF wicks up through the old one and ruins the TCM. Do a full fluid and filter change while the pan is off. DIY kit + plate runs $250-450 in parts; shop labor adds $400-800. Continuing to drive in limp mode can damage clutches and turn this into a $3000+ rebuild.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- OEM 140-270-11-61 722.6 conductor plateOEMMercedes-Benz/OEM 140-270-11-61
722.6 electrical/conductor plate after input/output speed-sensor or plate-circuit failure is confirmed Fitment/availability: The inspected direct product page identifies OEM 140-270-11-61, cross-reference 1402701161, and lists C-Class ap…
- Genuine Mercedes-Benz 203-540-02-53 13-pin pilot bushing/connectorOEMMercedes-Benz 203-540-02-53
722.6 electrical connector sealing branch when leaking or required by the conductor-plate service procedure Fitment/availability: The direct OEM dealer page identifies 203-540-02-53, lists its superseded connector numbers, describes the …
- Transtar A78010A/78300A 722.6 filter and pan-gasket kitOEMTranstar A78010A / 78300A; OE refs 140-277-00-95 / 140-271-0
Filter and pan-gasket service branch while an eligible 722.6 valve body is removed Fitment/availability: The inspected direct page identifies filter/gasket kit A78010A/78300A, interchanging with Mercedes 140-277-00-95 and 140-271-00-80, …
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Sources for this issue (3)
The 722.9 7G-Tronic automatic transmission fitted to ML350, ML500/550 and other gasoline M-Class models uses an internal conductor plate that doubles as the transmission control module and houses the input/turbine speed sensors. Heat, ATF breakdown and vibration cause the molded-in speed sensors and the plate's electronics to degrade internally. The transmission then loses the ability to monitor input-shaft speed and torque-converter slip, producing harsh, delayed or 'thumping' shifts that start out intermittent and eventually become permanent. In the worst case the transmission locks into a single gear (typically 2nd) and enters limp mode. This is one of the most widely reported 7G-Tronic faults across the W164/W166 M-Class. Repair is plug-and-play once codes are cleared with a STAR/equivalent scanner.
Common Symptoms
- Harsh or delayed gear changes
- Thumping or kicking on shift
- Transmission stuck in one gear
- Limp mode
- Check engine light
- Reduced fuel economy
How to Fix
Diagnose with a Mercedes STAR (or equivalent) scanner. Replace or refurbish the conductor plate (TCM); the connecting 13-pin transmission plug/adapter and ATF + filter are usually replaced at the same time. After installation the stored transmission and body codes MUST be cleared with the scanner or the car will remain in limp mode. Rebuilt/refurbished conductor plates are a much cheaper alternative to full valve-body or transmission replacement.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- OE-supplier Mercedes 722.9 conductor plate 000270260080OEMMercedes-Benz 000270260080
Guided-test-confirmed 722.9 conductor-plate/TCM failure on an EPC-confirmed M-Class application Fitment/availability: The inspected direct U.S.
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Sources for this issue (3)
P0717 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0717 mean on a Mercedes-Benz?
P0717 stands for "Input/Turbine Speed Sensor Circuit No Signal." This transmission code means the computer is receiving no signal from the input/turbine speed sensor, which measures how fast the transmission's input shaft (turbine side of the torque converter) is spinning. The computer compares this against engine and output speeds to control shifts and torque converter lockup. With no signal, it can't manage shifting properly, so you may get harsh or erratic shifts, no torque converter lockup, or limp mode. It is a no-signal electrical fault pointing to the sensor or its circuit. On Mercedes-Benz it is documented across 4 models: E-Class, SLK/SLC, C-Class, M-Class.
What are the most common causes of P0717?
The most common causes of P0717 are: Failed input/turbine speed sensor, Open or shorted wiring to the sensor, Corroded or loose sensor connector, Damaged reluctor/tone ring on the input shaft, Metal debris on the sensor tip from internal wear, Poor ground or reference voltage to the sensor, Faulty transmission control module (less common). The specific cause varies by vehicle.
How much does it cost to fix P0717 on a Mercedes-Benz?
Published repair estimates on Mercedes-Benz range from $300 to $2,200 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0717 on a different make?
View P0717 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.