P0742 Mercedes-Benz Code - Torque Converter Clutch Circuit Stuck On
Quick Answer
The Torque Converter Clutch (TCC) solenoid valve is activated, with the gear in D4, by the Transmission Control Module (TCM) in response to signals sent from the vehicle speed and the Engine Control Module (ECM). Common causes include Low transmission fluid level, Dirty transmission fluid, Faulty torque converter clutch solenoid valve. 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
- P0742 Mercedes-Benz indicates Torque Converter Clutch Circuit Stuck On.
- Common causes
- Common causes include Low transmission fluid level, Dirty transmission fluid, Faulty torque converter clutch solenoid valve.
- 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.
Code P0742 Mercedes-Benz Description
Lock-up operation, however, is prohibited when A/T fluid temperature is too low.
When the accelerator pedal is depressed (less than 2/8) in lock-up condition, the engine speed should not change abruptly. If there is a big jump in engine speed, there is no lock-up.
What are the Possible Causes of the DTC P0742 Mercedes-Benz?
- Low transmission fluid level
- Dirty transmission fluid
- Faulty torque converter clutch solenoid valve
- Torque converter clutch solenoid valve harness or connectors
- Torque converter clutch solenoid valve circuit is open or shorted
- Transmission internal mechanical problem
How to Fix the DTC P0742 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.
Code Tech Notes
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0742 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.
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Frequently Asked Questions about P0742 Mercedes-Benz Code
1. What does the OBDII code P0742 mean on a Mercedes-Benz?
P0742 indicates that the torque converter clutch (TCC) circuit is stuck in the "on" position, meaning the clutch is not disengaging as it should.
2. What are the symptoms of the P0742 code on a Mercedes-Benz?
Common symptoms include poor fuel efficiency, transmission overheating, shuddering while driving, difficulty accelerating, or the engine stalling when coming to a stop.
3. What causes the P0742 code on a Mercedes-Benz?
Possible causes include a faulty torque converter clutch solenoid, damaged wiring or connectors in the TCC circuit, low or contaminated transmission fluid, or an internal transmission issue.
4. Can I drive my Mercedes-Benz with the P0742 code?
Driving with this code is not recommended, as it can cause further damage to the transmission and lead to unsafe driving conditions.
5. How do I fix the P0742 code on a Mercedes-Benz?
Repairs may include replacing the TCC solenoid, repairing damaged wiring, flushing and replacing the transmission fluid, or addressing internal transmission issues.
6. How much does it cost to fix the P0742 code on a Mercedes-Benz?
Repair costs vary depending on the root cause but can range from $150 for a solenoid replacement to over $1,000 for more extensive transmission repairs.
7. How do I diagnose the P0742 code on my Mercedes-Benz?
Diagnosis involves using an OBDII scanner to confirm the code, inspecting the TCC solenoid and wiring, checking the transmission fluid condition, and performing a transmission pressure test if necessary.
8. Can low transmission fluid cause the P0742 code?
Yes, low or contaminated transmission fluid can prevent the torque converter from functioning properly, potentially triggering the P0742 code.
9. Does the P0742 code always mean the torque converter is bad?
No, the code could also be caused by electrical issues, a faulty TCC solenoid, or other transmission-related problems.
10. Will resetting the code fix the P0742 problem on a Mercedes-Benz?
Resetting the code may temporarily clear it, but the underlying issue must be addressed to prevent the code from returning and avoid further damage.
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