P0790 Mercedes-Benz Code - Normal/Performance Switch Circuit Malfunction
Quick Answer
The Transmission Control Module (TCM) monitors the Normal/Performance Switch signal. Common causes include Faulty Normal/Performance Switch, Normal/Performance Switch harness is open or shorted, Normal/Performance Switch circuit poor electrical connection. 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
- P0790 Mercedes-Benz indicates Normal/Performance Switch Circuit Malfunction.
- Common causes
- Common causes include Faulty Normal/Performance Switch, Normal/Performance Switch harness is open or shorted, Normal/Performance Switch circuit poor electrical connection.
- 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 P0790 Mercedes-Benz Description
What are the Possible Causes of the DTC P0790 Mercedes-Benz?
- Faulty Normal/Performance Switch
- Normal/Performance Switch harness is open or shorted
- Normal/Performance Switch circuit poor electrical connection
How to Fix the DTC P0790 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 is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0790 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 P0790 Mercedes-Benz Code
Q1: What does the OBDII code P0790 mean for a Mercedes-Benz?
A1: Code P0790 indicates a malfunction in the Normal/Performance switch circuit, which may affect the vehicle's driving mode selection.
Q2: What are common symptoms of P0790 in a Mercedes-Benz?
A2: Symptoms include inability to switch driving modes, reduced performance, transmission stuck in one mode, or the check engine light turning on.
Q3: What causes the P0790 code in Mercedes-Benz vehicles?
A3: Common causes include a faulty mode selector switch, damaged wiring, loose connectors, or a malfunctioning transmission control module (TCM).
Q4: Can I continue driving my Mercedes-Benz with the P0790 code?
A4: While the vehicle may be drivable, continued use can lead to poor performance or further damage to the transmission system.
Q5: How do I diagnose a P0790 code on a Mercedes-Benz?
A5: Use an OBDII scanner to retrieve the code, visually inspect wiring and connectors, test the mode selector switch, and check for TCM issues.
Q6: How can I fix the P0790 code on my Mercedes-Benz?
A6: Repairs may include replacing the mode selector switch, fixing damaged wiring, securing loose connections, or reprogramming/repairing the TCM.
Q7: How much does it cost to fix the P0790 code in a Mercedes-Benz?
A7: Repair costs can range from $100 to $500 depending on whether it's a simple wiring fix or replacement of parts like the mode selector switch.
Q8: Is the P0790 code related to transmission issues in Mercedes-Benz vehicles?
A8: Yes, it directly affects the transmission's ability to switch between driving modes, potentially impacting overall transmission performance.
Q9: Can a dead battery cause the P0790 code in a Mercedes-Benz?
A9: It's possible; a weak or dead battery can disrupt electrical circuits and communication with the mode selector switch.
Q10: Should I clear the P0790 code without repairs on my Mercedes-Benz?
A10: Clearing the code without addressing the underlying issue may temporarily turn off the check engine light but won’t resolve the problem.
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