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Ford C-Max 1.6tdci 2005 - Intermittent Fault Code U0073: CAN Bus Communication Issue

Model: Ford C-Max Fault Code: U0073 Posted: 2015-01-23 06:27

Hi, I own a Ford C-Max 1.6tdci from 2005 with approximately 100,000 miles. The vehicle is currently exhibiting an intermittent fault where the injector voltage and pulse are being lost. This issue is triggered by fault code U0073, indicating a loss of communication on the control module's CAN bus. Notably, the problem resolves itself before I can reach the location where it occurs — meaning the fault appears to be transient or conditionally triggered. I'm seeking advice on possible causes and solutions for this recurring yet intermittent issue, especially given that the vehicle is stock and no major modifications have been made.

Related fault codes
U0073
Comments (4)
Anonymous 2015-01-23 09:41

Fault code U0073 typically points to a CAN bus communication failure. While the vehicle appears to be stock, aftermarket equipment — even if not directly installed on the vehicle — can interfere with the CAN network. This is especially common when non-Ford-approved devices or accessories are connected. I don't work specifically on this model, but I have extensive experience with Ford vehicles. It's worth checking whether any aftermarket components (such as audio systems or navigation) could be disrupting the communication between modules.

Anonymous 2015-01-23 12:07

Hi Kev, yes — the vehicle is stock and has no major modifications. The only aftermarket component is the diagnostic equipment used to read fault codes, which is not a genuine Ford module or system.

Anonymous 2015-01-24 12:57

Any aftermarket device added to the vehicle — even if it's not directly connected to the electrical system — can interfere with the CAN bus. It's important to confirm exactly what components were installed, as even non-vehicle accessories may cause U0073 or similar communication faults.

Anonymous 2015-01-25 03:07

The vehicle is confirmed stock. The issue arises only when using aftermarket diagnostic equipment — not a genuine Ford module — to read the fault codes. This suggests that the problem may stem from signal interference rather than a hardware failure in the vehicle itself.