B1340 — Chime Input Request Circuit Short To Ground

Is it safe to drive with B1340?

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 do I diagnose B1340 myself?

Start with a scan: confirm B1340, 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 are the symptoms of B1340?

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.

Will B1340 clear itself?

Sometimes B1340 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.

How much does it cost to fix B1340?

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

When your scan tool displays B1340, the vehicle's body control module has detected that an electrical circuit is pulling current to ground when it should not be. The official definition reads "Chime Input Request Circuit Short To Ground," which puts this trouble code squarely in the body electrical category. This is not an engine or transmission fault—it lives in the network of switches, motors, and control modules that manage doors, windows, lighting, wipers, and similar features.

The body control module continuously monitors voltage and resistance across the circuits it governs. It does this by comparing real-time sensor readings against factory-calibrated thresholds. When a chime input request circuit drops to near-zero voltage—indicating an unintended path to ground—the module logs B1340 and illuminates the check engine or body warning light. Most manufacturers require the condition to persist across multiple drive cycles before confirming the fault, which is why the code sometimes appears after a few days of normal driving rather than immediately after a problem starts.

One of the most useful diagnostic tools for B1340 is the freeze frame data stored alongside the code. This snapshot captures engine speed, load, coolant temperature, and vehicle speed the instant the fault was detected. Reviewing this information first tells you whether B1340 appeared during cold startup, highway cruising, or a specific weather condition—clues that point you toward the actual culprit faster.

Symptoms of B1340

• Check engine or body warning light stays on
• Affected system operates intermittently or stops working entirely
• Central locking behaves erratically or fails to respond
• Power windows, mirrors, or seats malfunction
• Interior or exterior lighting flickers or goes out
• Wipers operate abnormally or refuse to turn on
• Engine performance remains unaffected in most cases

Common Causes of B1340

• Body control module internal failure or software corruption
• Blown fuse or faulty relay feeding the affected circuit
• Wiring damaged by flex cycles at door jambs, hatches, or hinges
• Connectors corroded by moisture intrusion or road salt
• Loose or pushed-back terminals at the wiring harness
• Failed switch, actuator motor, or sensor in the affected system
• Aftermarket accessory installation that overloads the circuit

How to Diagnose B1340

1. Plug in an OBD2 scanner, retrieve B1340, and record all freeze frame data before clearing anything. Note the engine conditions when the fault occurred—this narrows your focus considerably.

2. Scan for additional trouble codes. B1340 often accompanies other body system faults, and the pattern tells you whether the BCM itself is the problem or whether a single failing component is dragging the whole circuit down.

3. Check manufacturer TSBs for your specific make, model, and year. The B0xxx family of codes appears across many platforms, and several have documented software updates or known hardware weaknesses. Searching by VIN on the manufacturer portal or nhtsa.gov surfaces relevant service campaigns.

4. Perform a hands-on inspection of wiring and connectors feeding the malfunctioning system. Look for cracked insulation, broken strands hidden under tape, green corrosion buildup, and any connector where the locking tab is broken or missing.

5. Activate the problem function—lock the doors, roll up a window, flip the wipers—and monitor live data PIDs for the corresponding switch and motor. Inconsistent readings as you operate the control confirm a physical fault in that component.

6. Clear B1340 and complete a drive cycle that recreates the conditions stored in the freeze frame. If the code returns, the fault is confirmed and present under normal operation.

Repair Options and Costs

The repair strategy for B1340 depends entirely on what the diagnosis reveals. Always investigate the simple, inexpensive possibilities before committing to major component replacement.

• Switch or actuator replacement: $120–$450 (parts and labor)
• Wiring harness or connector repair: $80–$250 (parts and labor)
• BCM repair or replacement: $300–$900 (parts and labor)

Total Repair Cost for B1340

The full bill for resolving B1340 typically falls between $80 and $900 depending on the root cause. A loose connector behind the driver kick panel might cost under a hundred dollars in labor plus minimal parts, while a failed body control module on a luxury vehicle approaches the high end. Spending thirty to sixty minutes on accurate diagnosis before purchasing parts almost always costs less than guessing wrong on a $400 BCM.

Can You Drive with B1340?

In most vehicles, B1340 poses no direct threat to engine operation or vehicle control—you can continue driving without damaging the drivetrain. That said, the underlying malfunction may involve exterior lighting, wipers in rain or snow, or central locking. A lighting failure creates a safety hazard at night, and a non-functional locking system leaves the vehicle unsecured. Address these specific risks promptly even if the car otherwise drives normally.

Related OBD2 Codes

• B1300: Power Door Lock Circuit Failure
• B1301: Power Door Lock Circuit Open
• B1302: Accessory Delay Relay Coil Circuit Failure
• B1303: Accessory Delay Relay Coil Circuit Open
• B1304: Accessory Delay Relay Coil Circuit Short To Battery
• B1305: Accessory Delay Relay Coil Circuit Short To Ground