Control Module Power Supply Voltage Range Performance Problem
Low voltage detected at the control module power supply.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The control module isn't getting enough power; this can happen if the battery is weak, there's a bad connection, or a wire is damaged.
What the computer is actually seeing
The control module detects input voltage below the expected range, usually below 9 volts for proper operation.
What a healthy reading looks like
Expected voltage at the control module power supply should be between 10 to 14 volts with the engine running.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Check battery voltage; it should be above 12.4 volts. If below, charge or replace the battery.
- 22. Inspect battery terminals for corrosion or loose connections; clean or tighten as needed.
- 33. Check the wiring harness and connectors leading to the control module for any signs of damage or corrosion. Repair as necessary.
- 44. Measure the voltage at the power supply pin of the control module with the key on and engine off. Should be between 10-14 volts. If not, trace back to the power source.
- 55. If voltage is good but the code still exists, consider testing or replacing the control module.
Common causes
- Weak or discharged battery
- Corroded battery terminals
- Damaged wiring or connectors
- Faulty control module
- Faulty ignition switch
Typical repair cost
$$-$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It may be, but expect possible electrical system issues. Fix it soon.
Will the code come back after clearing?
Yes, if the underlying issue isn't resolved, it will likely return.
Why do I also see codes B101A and B101C?
These codes are related to similar power supply issues within the vehicle's electronic systems.
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