Mercedes P0715 P0720 P0700: Limp Mode Causes, Repair Cost and the 722.6 Conductor Plate Fix

Last updated: October 27, 2026

Is your Mercedes-Benz stuck in second gear (limp mode), and the check engine light came on? You are experiencing transmission problems. You press the gas pedal, and the engine RPMs rise to 4000 or even higher, but you are limited to a maximum speed of about 30 MPH. The check engine light (CEL) comes on. Scan the car using an OBD-II code reader and get fault codes such as P0715, P0720, and P0700. Diagnostic Trouble Code (DTC) P0715 is detected when the TCM or ECM does not receive the signal from the input/turbine speed sensor.

Quick Tip If you need to get home, try turning off the car. Remove key and wait a couple of minutes then restart the car. You may be lucky and get the car out of limp mode. It is a matter of time before your Mercedes-Benz goes back into limp mode. Get your transmission problem resolved. Read on to learn how to troubleshoot and fix the most common Mercedes Benz automatic transmission problems.

Mercedes Automatic Transmission Fault Codes

Here is a list of error codes related to Mercedes 5-speed and 7-speed automatic transmissions.

• P0720: Output Speed Sensor Circuit Malfunction
• P0715: Input/Turbine Speed Sensor Circuit Malfunction (Transmission Conductor Plate or 13-pin connector issue)
• P0700: Transmission Control System Malfunction (Generic Code telling you there is a transmission problem)
• P0716, P0717, P0718: Input / Turbine Speed Sensor Circuit Malfunction / Range Performance / No Signal / Intermittent
• P0719: Torque Converter Brake Switch Circuit Low

All these fault codes indicate a powertrain malfunction, typically related to automatic transmission problems.

Symptoms

• Mercedes-Benz does not shift properly
• Check Engine Light / Service Engine Light On
• Stuck in second gear / Limp Mode
• High Engine RPM
• Limited Max Speed of 30 MPH

Possible Causes

In most cases, the problem is one of the following:

View on Amazon →Mercedes Benz Valve Body 722.6 5 Speed Transmission

View on Amazon →Defective Conductor Plate

View on Amazon →Failed 13-pin connector harness, Leaks Oil, Transmission O-Ring

Cost to Fix P0715, P0720 and P0700

The good news is that to repair any of the problems mentioned above, you don’t need to remove the Transmission from the car. You can perform the repairs with the Transmission in place. The most expensive repair could cost a few hundred dollars.

The first thing to check is the 13-pin connector plug. This is the electrical wire harness that plugs into the valve body inside the Transmission. It leaks oil and causes communication problems between the transmission control unit and the sensors on the valve body. This part costs less than $20 and can be found on Amazon. Follow this article on How to replace the 13-pin connector on the Mercedes-Benz transmission.

If the valve body conductor plate is the problem, you’ll need to spend $150 to $250 on a new conductor plate. Depending on your location, auto repair shops may charge between $650 and $950. The Mercedes-Benz dealership quoted between $1400 and $1800 for this repair. One place to find conductor plates for Mercedes-Benz 5-Speed 722.6 and 7-speed 722.9 transmissions is Amazon. If your car has the 722.9 seven speed, read our 722.9 valve body and conductor plate guide first; the part and the procedure differ.

How to replace the valve body

If the 13-pin connector doesn’t fix the problem, the next step is to replace the valve body conductor plate. Replacing the conductor plate is easy. It is mounted on top of the valve body. You will need to remove the valve body from the Transmission. The Transmission doesn’t need to be replaced. The valve body can be removed from underneath. Replace the conductor plate and reinstall the valve body. The pan and the fluid come out in the process, so this is the moment to do the 722.6 fluid and filter change as well.

DIY Troubleshooting

The codes listed above give you a general idea of what’s wrong with the car. They are fault codes stored on the Engine Control Unit (ECU); you get them from a generic OBD II scanner. To properly troubleshoot the transmission problem on your Mercedes-Benz, you will need a diagnostic scanner to retrieve the fault codes from the transmission control unit (TCU). The next step is to get hold of such an advanced diagnostic scanner and read the TCU error codes, which will help you narrow down the problem with your Mercedes-Benz. A scanner that reads the transmission control unit also reads the ABS, ESP and the other modules on the car, so it is worth owning rather than paying a shop for each code read.

If you want to read more about diagnostic scanners that work on Mercedes-Benz, you may find this article helpful: Top 10 Best Diagnostic Scanners for Mercedes-Benz.

Once you fix the problem, such as replacing the 13-pin connector or the valve body, you will need a scanner that can clear the transmission control unit, not just the engine codes, to get the car out of limp mode.

How to Read and Erase Transmission Fault Codes

Use an advanced scanner to read the fault codes from the transmission control module. Fix the problem specific to your car, then use the OBD-II scanner to clear the fault codes and get the car out of limp mode. Watch the video using the scanner above to read and clear the fault codes.

Possible Solutions

Depending on the outcome of your troubleshooting, here are some articles that can help you repair problems with your Mercedes-Benz.

Still having Automatic Transmission Problems

If your Mercedes-Benz transmission is still acting up, other reasons could cause it to shift erratically, be stuck in second gear, limp mode, stuck in park, or other problems. Read Mercedes-Benz Automatic Transmission Problems and Solutions article if you need more help.

Applicable Models

The 722.6 was also fitted outside the Mercedes-Benz range, so the same problem turns up on the Chrysler Crossfire, the Dodge and Freightliner Sprinter vans and the Mercedes-Benz SLR McLaren.

Mercedes-Benz Transmission Valve Body Electrical Conductor Plate (5-Speed 722.6xx Transmission) 1402701161: 1994-1997 5-Speed A/T SL320 / 1994-2006 5-Speed A/T SL500 / 2003-2007 5-Speed SL55 AMG / 1994-2007 SL600 / 2005-2007 SL65 AMG / 1998-2004 SLK230 / 2002-2004 SLK32 AMG / 2001-2004 SLK320 / 2010 Mercedes-Benz Sprinter 2500 3500 / 2003-2009 Dodge Sprinter 2500 3500 / 2002-2010 Freightliner Sprinter 2500 3500

Impacted Mercedes-Benz models, 1997 to 2007: C230, C240, C32 AMG, C320, C55 AMG, CL500, CL55 AMG, CLK320, CLK500, CLK55 AMG, E300, E320, E420, E430, E500, E55 AMG, ML320, ML350, ML430, ML500, ML55 AMG, S430, SL320, SL500, SL55 AMG, SL600, SLK320, SLK32 AMG and the Sprinter.

Getting Out of Limp Mode After the Repair

Replacing the 13-pin connector or the conductor plate does not by itself end limp mode. The transmission control unit keeps the fault stored and may hold the car in its protection program until that code is cleared from the transmission module, which a generic engine code reader cannot do: the P0700 you read at the OBD port is the engine computer relaying that the transmission has a problem, and the detail, which speed sensor, whether the fault is current or stored, lives in the transmission control unit. A scanner that reads every control unit, such as the UCAN-II Pro, reads the transmission codes directly, clears them after the repair and shows the turbine and output speed sensor readings live, so you can see the new conductor plate reporting before you drive the car.