Cause
Failed power or earth supply to the module
The module's own supply rather than anything it controls. Modules starved of voltage misbehave rather than dying, so they record faults naming healthy parts.
The procedure matters as much as the diagnosis: fix the supply, clear the codes, drive the vehicle, then re-read. What comes back is real.
Typically a moderate job.
Some of these codes mean you should stop driving
12 of the 163 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 (163)
Codes where this is a likely explanation first, rather than merely a possible one.
- P0A1A Generator Control Module Likely for this code Moderate
- P0A1B Drive Motor A Control Module Performance Likely for this code High
- P0A1C Drive Motor B Control Module Performance Likely for this code High
- P0A1D Hybrid/EV Powertrain Control Module A Likely for this code High
- P0A1E Starter/Generator Control Module Likely for this code Moderate
- P0A1F Battery Energy Control Module A Performance Likely for this code High
- P0A78 Drive Motor A Inverter Performance Likely for this code High
- P0A79 Drive Motor B Inverter Performance Likely for this code High
- P0A7A Generator Inverter Performance Likely for this code High
- U0074 Control Module Communication Bus B Off Likely for this code High
- U0100 Lost Communication With Engine Control Module A Likely for this code Stop driving High
- U0101 Lost Communication With Transmission Control Module Likely for this code High
- U0103 Lost Communication With Gear Shift Control Module A Likely for this code High
- U0105 Lost Communication With Fuel Injector Control Module Likely for this code Stop driving High
- U0106 Lost Communication With Glow Plug Control Module 1 Likely for this code Moderate
- U0107 Lost Communication With Throttle Actuator A Control Module Likely for this code Stop driving High
- U0109 Lost Communication With Fuel Pump Control Module A Likely for this code Stop driving High
- U010C Lost Communication With Turbocharger/Supercharger Control Module A Likely for this code High
- U010E Lost Communication With Reductant Control Module Likely for this code High
- U0110 Lost Communication With Drive Motor Control Module A Likely for this code Stop driving High
- U0111 Lost Communication With Battery Energy Control Module A Likely for this code Stop driving High
- U0113 Lost Communication With Emissions Critical Control Information Likely for this code High
- U0115 Lost Communication With Engine Control Module B Likely for this code Stop driving High
- U0116 Lost Communication With Coolant Temperature Control Module Likely for this code Moderate
- U0119 Lost Communication With Fuel Cell Control Module Likely for this code Stop driving High
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.
Others who found this
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Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
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