Cause
Another module holding the bus down
One failed module can drag the shared network down for everything on it. So a scan tool listing lost-communication codes for a dozen modules is describing one fault, not a dozen — and the module at fault is generally not one of the modules named, since a module that has stopped talking cannot report anything.
Disconnecting modules one at a time until the bus recovers is the standard method, and it is why this belongs before any module is replaced.
Typically specialist work. Needs equipment or training most home workshops do not have.
Some of these codes mean you should stop driving
9 of the 58 codes this can cause indicate a fault where continuing to drive risks damage or is unsafe. Which one you have matters more than the cause does — read the code's own page before deciding.
Codes this can cause (58)
Codes where this is a likely explanation first, rather than merely a possible one.
- U0001 High Speed CAN Communication Bus Likely for this code Stop driving High
- U0028 Vehicle Communication Bus A Likely for this code High
- U0040 Vehicle Communication Bus B (+) Low Likely for this code High
- U0043 Vehicle Communication Bus B (-) Low Likely for this code High
- U0055 Vehicle Communication Bus D Likely for this code Moderate
- U0058 Vehicle Communication Bus D (+) Low Likely for this code Moderate
- U0061 Vehicle Communication Bus D (-) Low Likely for this code Moderate
- U0073 Control Module Communication Bus A Off Likely for this code High
- U0074 Control Module Communication Bus B Off Likely for this code High
- U0075 Control Module Communication Bus C Off Likely for this code High
- U0100 Lost Communication With Engine Control Module A Likely for this code Stop driving High
- U0113 Lost Communication With Emissions Critical Control Information Likely for this code High
- U0248 Lost Communication With Remote Accessory Module Likely for this code Low
- U0293 Lost Communication With Hybrid/EV Powertrain Control Module Likely for this code Stop driving High
- U0447 Invalid Data Received From Serial Data Gateway Module A Likely for this code High
- U0493 Invalid Data Received From Personal Computer Likely for this code Low
- U0002 High Speed CAN Communication Bus Performance High
- U0004 High Speed CAN Communication Bus (+) Low Stop driving High
- U0007 High Speed CAN Communication Bus (-) Low Stop driving High
- U0010 Medium Speed CAN Communication Bus Moderate
- U0031 Vehicle Communication Bus A (+) Low High
- U0034 Vehicle Communication Bus A (-) Low High
- U0037 Vehicle Communication Bus B High
- U0046 Vehicle Communication Bus C Moderate
- U0067 Vehicle Communication Bus E (+) Low Moderate
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
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