What it means
Control Module Input Power B Circuit Range/Performance: the signal is implausible or outside the valid range.
At a glance
- Usually lights the warning light of the system that lost communication
How it works
The module checks whether its B input-power signal behaves within the expected range for the operating conditions. This code sets when the B reading is implausible or outside that range, even if it is not simply too low or too high.
Common causes
Most likely first.
- High resistance in supply path
- Gateway module routing CAN messages incorrectly
- CAN terminating resistor (120 Ω) drifted out of spec
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
How to diagnose it
- Record freeze-frame data and scan all modules for related voltage and communication codes to see whether the B-signal fault appears with other network problems.
- Inspect the module’s B-feed connector, wiring, fuse, and ground for corrosion, looseness, damage, or excessive resistance.
- Compare the B input reading on a scan tool with a meter reading at the module under the same conditions.
- Measure voltage drop through the B supply path under the manufacturer's specified load to check for resistance that could distort the reading.
- If the supply and ground are sound, check gateway routing and CAN wiring and termination using the vehicle wiring diagram and manufacturer's procedures.
Common fixes
- Clean and secure a poor connection in the B-feed circuit.
- Repair damaged or high-resistance B-feed wiring or ground connections.
- Replace a faulty fuse terminal or connector pin.
- Repair a confirmed gateway or CAN network fault if B-feed measurements are correct.
Can I keep driving?
The code alone does not confirm an immediate loss of control, but the module may shut down or dependent systems may behave unpredictably. Avoid driving if steering, braking, powertrain, or other safety-related functions are affected; otherwise arrange prompt diagnosis.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.