AutoCodes – Mercedes-Benz – P0747 Mercedes-Benz

P0747 Mercedes-Benz Code - Pressure Control Solenoid 'A' Stuck On

Quick Answer

The Pressure Control (PC) Solenoid Valve an electronic pressure regulator that controls transmission line pressure based on current flow through its coil windings. Common causes include Low transmission fluid level, Dirty transmission fluid, Faulty Pressure Control Solenoid. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P0747 Mercedes-Benz indicates Pressure Control Solenoid 'A' Stuck On.
Common causes: Common causes include Low transmission fluid level, Dirty transmission fluid, Faulty Pressure Control Solenoid.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 3,356

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jan 29, 2019

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0747 Mercedes-Benz Description

The Pressure Control (PC) Solenoid Valve an electronic pressure regulator that controls transmission line pressure based on current flow through its coil windings. As current flow is increased, the magnetic field produced by the coil moves the solenoid’s plunger further away from the exhaust port. Opening the exhaust port decreases the output fluid pressure regulated by the PC solenoid valve, which ultimately decreases line pressure. The line pressure solenoid valve regulates the oil pump discharge pressure to suit the driving condition in response to a signal sent from the Transmission Control Module (TCM).

OBDII Code P0747 Mercedes-Benz - Pressure Control Solenoid 'A' Stuck On - AutoCodes.com — P0747 Mercedes-Benz Code - Pressure Control Solenoid 'A' Stuck On

What does this mean?

What are the Possible Causes of the DTC P0747 Mercedes-Benz?

Low transmission fluid level
Dirty transmission fluid
Faulty Pressure Control Solenoid
Pressure Control Solenoid harness is open or shorted
Pressure Control Solenoid circuit poor electrical connection

How to Fix the DTC P0747 Mercedes-Benz?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

When a transmission solenoid is malfunctioned, in most cases the problem is not the electrical part of the solenoid; the problem is foreign material obstructing the mechanical function of the solenoid or the flow of the fluid through the transmission valve body. If the transmission fluid is dirty, it's recommended to change the transmission fluid and if possible removing the transmission pan for further diagnosis. Excessive debris or metal particles on the transmission pan could be an indication that there is a mechanical transmission failure and that the transmission will need to be rebuilt or replaced.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0747 Mercedes-Benz code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0747 Mercedes-Benz code?

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0747 Mercedes-Benz Code

1. What does the OBDII code P0747 mean on a Mercedes-Benz?

P0747 indicates that the transmission control module (TCM) has detected that the Pressure Control Solenoid 'A' is stuck in the "on" position, causing potential transmission performance issues.

2. What are the common symptoms of code P0747 in a Mercedes-Benz?

Symptoms may include harsh or delayed shifting, a slipping transmission, reduced fuel efficiency, the transmission being stuck in one gear (limp mode), and the check engine light being illuminated.

3. What causes the P0747 code on a Mercedes-Benz?

Common causes include a faulty pressure control solenoid, low or dirty transmission fluid, clogged transmission passages, wiring issues such as shorts or open circuits, or a malfunctioning transmission control module.

4. Can driving with the P0747 code damage my Mercedes-Benz?

Yes, continuing to drive with this code can lead to further transmission damage, as improper fluid pressure regulation can strain internal components.

5. How can I diagnose the P0747 code on my Mercedes-Benz?

Diagnosis involves using an OBDII scanner to confirm the code, checking the transmission fluid level and condition, inspecting the solenoid and its wiring for damage, and testing the solenoid's functionality with specialized tools.

6. How do I fix the P0747 code on a Mercedes-Benz?

Repairs may involve replacing the pressure control solenoid, flushing and refilling the transmission fluid, repairing or replacing damaged wiring, or, in rare cases, replacing the transmission control module.

7. Is the P0747 code a common issue in Mercedes-Benz vehicles?

While not extremely common, this code can appear in Mercedes-Benz models, especially if the vehicle has high mileage, poor maintenance history, or a known issue with the transmission system.

8. How much does it cost to fix the P0747 code on a Mercedes-Benz?

Repair costs can vary widely depending on the cause, ranging from $150 for a fluid change to $1,000 or more if the solenoid or transmission control module needs replacement.

9. Can low transmission fluid cause the P0747 code in a Mercedes-Benz?

Yes, low or dirty transmission fluid can contribute to this issue by affecting fluid pressure and solenoid operation.

10. Should I clear the P0747 code after repairs on my Mercedes-Benz?

Yes, after completing repairs, you should clear the code with an OBDII scanner and test drive the vehicle to ensure the issue is resolved and the code does not return.