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Mercedes CL203 Sport Coupe - Winter Cold Start Issue with P2310, P2311, P2312, and P2315 CAN Communication Faults

Model: Mercedes CL203 SPORT COUPE Fault Code: P2310 Posted: 2017-12-13 10:19

Hello everyone, I own a 2004 Mercedes-Benz CL203 Sport Coupe and am experiencing a recurring starting issue when the car has been idle for more than four days, especially during cold winter weather. The vehicle cranks but fails to start under these conditions. I previously took it to a local garage where they replaced the starter relay. After driving the car for a month, the problem returned after four days of inactivity. When I returned for further diagnosis, the mechanic was unable to resolve the issue. I then consulted an auto electrical specialist who diagnosed the following OBD2 fault codes: - P2310: CAN communication failure with the traction system - P2311: CAN communication failure with the engine management system - P2312: CAN communication failure with the engine system or implausible engine temperature reading - P2315: Fault in CAN communication with Control Unit A1 (Instrument cluster) These codes suggest a potential issue with the vehicle's CAN bus network, possibly related to electrical voltage drops or faulty control units. I'm seeking advice on how to interpret these codes and whether I should pursue repair at a Mercedes-Benz dealership or consider alternative solutions. Any insights would be greatly appreciated. Thanks, Feji

Related fault codes
P2310P2311P2312P2315
Comments (5)
Anonymous 2017-12-13 10:39

Check the battery voltage during cranking — it should remain above 10V. If the engine is laboring when trying to start, low voltage could be causing CAN communication faults. Also verify alternator output while the engine is running; it should read at least 13.5V.

Anonymous 2017-12-14 03:12

Thanks for the tip, CJ. I've already tested the battery and confirmed it's not the issue. I’ve also read several negative reviews about Mercedes-Benz dealership service quality. Some mechanics here suggest problems with fuel injectors or water in the SAM fuse — but none have been able to confirm these issues.

Anonymous 2017-12-14 09:41

For a reliable diagnosis, especially on older Mercedes models like the CL203, it's best to take the vehicle to an official Mercedes-Benz specialist. If system voltage is stable, a professional diagnostic tool and CAN bus analysis are essential for accurate troubleshooting.

Anonymous 2017-12-31 23:00

After visiting a Mercedes-Benz dealership, they confirmed that the Engine Control Unit (ECU) is damaged. The unit was disconnected and sent for testing — the result showed it cannot be repaired. The replacement ECU costs €1,963. Given the vehicle's age and value, I'm wondering if it would be more cost-effective to purchase a compatible third-party ECU from eBay and have a Mercedes specialist reprogram it. Any advice on this option? Fejiro

Anonymous 2018-01-02 10:39

I don't have a definitive answer, but I can say that repair costs at Mercedes dealerships are often very high — especially for older models with complex ECU systems. This makes long-term ownership and maintenance financially challenging.