Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC P1648 (64): Battery Condition Monitor (BCM) Module Communication Signal Circuit Problem: General Description
Data is transmitted and received between the MCM (motor control module) and the BCM (battery condition monitor) module. Various commands are included in the data stream, and commands are not completed, which is normal, when there is an open in the line or a faulty circuit for the interface. The MCM confirms the validity of the data received according to the parity and check sum, and it measures a time interval during which the command update has not been executed based on updates by the internal timer. If no data update is executed over a set time, a malfunction is detected and a DTC is stored.
| Execution | Continuous |
| Sequence | None |
| Duration | 2 seconds or more |
| DTC Type | One drive cycle, MIL ON, IMA system indicator ON |
| Condition | Minimum | Maximum |
|---|---|---|
| MCM power-supply voltage | 10.5 V | - |
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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