Fixing a Non-Starting BMW M6 V10 with a $10,000 SMG Pump

The Auction Purchase and Initial Problems

• 💡 A BMW M6 V10 was purchased at auction for $1,985, with the initial plan to sell parts from a second BMW to cover the M6's costs.
• 🎯 So far, only $150 has been made from selling parts off the donor car, leaving a significant deficit.
• ⚠️ The M6 itself presented with a sun-damaged dashboard and weak brakes upon arrival, but initially started and ran.
• 📉 After sitting for a few months, the M6 developed a no-start condition, refusing to even enter accessory mode.

Troubleshooting the No-Start Condition

• 🔍 Initial checks revealed a small amount of water intrusion in the trunk and fuse box area, which was cleaned.
• ⚡ A common trick involving the Intelligent Battery System (IBS) connector was attempted, leading to improved dashboard activity but still no start.
• 🚗 Diagnostic codes pointed to issues with the steering column lock and brake light switch, which were addressed without resolving the problem.
• 🧩 Further investigation into the transmission control module revealed low hydraulic pressure, a critical component for the SMG transmission's operation.

Diagnosing the SMG Hydraulic Pump Failure

• ⚙️ The SMG transmission on this M6 is an automated manual transmission that relies on a hydraulic system and clutch actuation.
• ⚠️ The diagnostic tool indicated a pressure buildup timeout, suggesting the hydraulic pump was not functioning.
• 🔊 Activating the hydraulic pump via the diagnostic tool produced no sound, while the gear oil pump could be heard.
• 💰 A genuine BMW SMG hydraulic pump was quoted at approximately $10,940, highlighting the extreme cost of replacement parts.

The "Old Trick" and Successful Start

• 🛠️ After confirming the pump itself was likely the issue, the team decided to test it directly by applying 12 volts.
• ⚡ Initial tests showed the pump was weak and intermittently working, with no amperage draw after a few attempts.
• 💡 A breakthrough occurred when tapping the pump with a hammer seemed to temporarily revive it, allowing the car to start.
• ✅ The BMW M6 V10 was successfully started, confirming that the SMG hydraulic pump was the primary cause of the no-start condition, despite initial assumptions about other issues.