B1671 — Battery Module Voltage Out Of Range

Is it safe to drive with B1671?

Usually safe to drive — body codes rarely affect drivability. Exceptions: exterior lighting and wipers in bad weather, and central locking faults that can leave the car unsecured.

How much does it cost to fix B1671?

Replace the switch or actuator — $120–$450; Repair wiring or connectors — $80–$250; BCM repair or replacement — $300–$900. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.

How do I diagnose B1671 myself?

Start with a scan: confirm B1671, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the body electrical system, and verify the suspect component against live data before buying parts.

What is the most common cause of B1671?

The most common causes are: corroded or loose connectors, blown fuse or failed relay, body control module (BCM) fault.

What are the symptoms of B1671?

Drivers most often notice: no impact on engine operation in most cases, warning light on the dashboard, the affected function (locks, windows, lighting, wipers) works intermittently or not at all.

When your OBD2 scanner pulls code B1671, it's telling you the body control module has detected a voltage reading that falls outside the acceptable range. The technical label for this fault is "Battery Module Voltage Out Of Range," and it lives in the B-body category alongside other body electrical codes. This isn't an engine or drivetrain problem—B1671 points specifically to the network of switches, motors, and control circuits that run your doors, windows, lights, and wipers.

The body control module (BCM) constantly monitors voltage at various points in the vehicle's auxiliary electrical system. It compares those live readings against factory-calibrated thresholds. If a reading strays too far above or below the acceptable window—typically across multiple drive cycles—the module logs B1671 and illuminates the check-engine or warning light. The stored freeze frame data captures engine speed, load, coolant temperature, and vehicle speed at the exact moment the fault triggered, which gives you a starting point rather than chasing symptoms blind.

Common Symptoms of B1671

• The malfunction indicator lamp (MIL) or a dedicated body-system warning light turns on and stays illuminated
• The specific function involved—power locks, windows, lighting, or wipers—operates erratically or stops responding entirely
• No change to engine performance or drivability in most cases; the vehicle still drives and shifts normally
• Intermittent operation where the affected system works sometimes and fails other times
• Possible BCM failsafe mode that disables multiple body functions simultaneously

What Causes B1671

Most B1671 faults trace back to a handful of recurring problems, listed here from most to least common:

• Corroded, loose, or unplugged electrical connectors in the body circuit
• Failed switch, motor, or actuator controlling the affected function
• Internal fault within the body control module itself
• Wiring insulation damage or broken conductors in high-flex areas like door jambs and tailgate hinges
• Poor ground connections at body electrical components
• Water intrusion into connectors or modules located in wet areas
• Blown fuses or fusible links protecting the affected circuit

How to Diagnose B1671

Follow these steps in order to isolate the root cause without replacing parts unnecessarily:

1. Connect an OBD2 scanner and confirm B1671 is stored, then record the freeze frame data—this snapshot shows what the engine was doing when the module detected the fault and narrows your search considerably.
2. Pull all other stored codes as well; related P-codes, C-codes, or additional B-codes often point directly to the failing component rather than the voltage anomaly itself.
3. Visually inspect the wiring harness and connectors tied to the body electrical system, paying close attention to areas exposed to moisture and to locations where wires bend repeatedly.
4. Activate the problem function (lock a door, roll up a window, turn on the wipers) while monitoring the relevant PIDs in your scanner's live data stream—watch for voltage drops or signal losses.
5. Check connectors at flex points: door hinges, tailgate openings, and any harness passage through sheet metal are the most likely spots for broken strands inside intact-looking insulation.
6. Clear the code, drive the vehicle through conditions matching the freeze frame snapshot, and verify that B1671 does not reappear—if it returns, you've narrowed the problem to whatever changed during that test cycle.

Repair Options and Costs

Once you've identified the failed component, repair costs vary based on what's actually wrong:

• Replace the faulty switch, motor, or actuator in the affected circuit: $120–$450 (parts and labor)
• Repair damaged wiring, terminals, or connectors: $80–$250 (parts and labor)
• Repair or replace the body control module: $300–$900 (parts, programming, and labor)

Total Cost to Fix B1671

For most vehicles, the total bill lands somewhere between $80 and $900, depending on which part failed. The switch or actuator is the most common culprit and the least expensive to fix. Module replacement sits at the high end and should only happen after you've ruled out every connector and wiring issue. Spending time on a thorough diagnosis before buying a new BCM will almost always save money— module replacement is rarely the first repair anyone needs for this code.

Can You Drive with B1671?

Short answer: yes, in most situations. Body electrical codes like B1671 typically do not affect engine operation, transmission function, or safety-critical drivetrain controls. However, there are exceptions worth considering. If the code stems from a failed exterior lighting circuit, you risk driving without proper illumination. Wiper motor failure becomes a genuine hazard in rain or snow. A malfunctioning central locking system could leave your vehicle unsecured. Use your best judgment—get the code diagnosed before a minor electrical fault becomes a visibility or security problem.

Related OBD2 Codes

• B1600: PATS Ignition Key Transponder Signal Is Not Received
• B1601: PATS Received Incorrect Key-Code From Ignition Key Transponder
• B1602: PATS Received Invalid Format Of Key-Code From Ignition Key Transponder
• B1603: Lamp Anti-Theft Indicator Circuit Failure
• B1604: Lamp Anti-Theft Indicator Circuit Open
• B1605: Lamp Anti-Theft Indicator Circuit Short To Battery

The B1671 OBD2 fault code relates to the Climate Control Air Temperature Internal Sensor Motor circuit. When the circuit open circuit, the module cannot properly monitor or control this body system.

At AIscanAuto, we help drivers quickly identify OBD2 trouble codes, understand their root causes, and find the right fix.

Symptoms

• Climate control not responding
• A/C pressure issues
• Temperature not adjusting
• Possible blower motor issues

Common Causes

• Faulty component — internal damage or wear affecting Climate Control Air Temperature Internal Sensor Motor
• Wiring issues — broken, corroded, or chafed wires in the circuit
• Connector problems — loose, oxidized, or moisture-damaged pins
• an open circuit is detected — indicates a break in the circuit path, resulting in no signal transmission
• Module input failure — rare, but the control module input stage may be defective

Step-by-Step Diagnosis

1. Scan with OBD2 tool — Confirm B1671 is active. Check for additional DTCs.
2. Visual inspection — Examine the Climate Control Air Temperature Internal Sensor Motor wiring and connector for corrosion or damage.
3. Check voltage and ground — Use a multimeter to verify proper reference voltage.
4. Test component — Compare readings to factory specs. A stuck or erratic signal confirms failure.
5. Check for shorts/opens — Perform continuity tests on the wiring between the component and control module.

Repair & Solutions

• If the component is defective, replace the Climate Control Air Temperature Internal Sensor Motor with an OEM or quality aftermarket part.
• Repair any damaged wiring or connectors using proper methods.
• Clear the DTC with an OBD2 scanner and test drive to verify the code does not return.
• If the code persists after component replacement, inspect the control module connector.

Related Codes

• B1668 — Climate Control Temperature Differential Circuit Short To Battery
• B1669 — Climate Control Temperature Differential Circuit Short To Ground
• B1670 — Climate Control Air Temperature Internal Sensor Motor Circuit Failure