OBD2 Code B1340: Chime Input Circuit Short to Ground
The B1340 code indicates that the Instrument Cluster Module (ICM) or Body Control Module (BCM) has detected a short to ground in the chime request input circuit. This circuit controls the audible chime that alerts the driver to conditions such as open doors, keys left in the ignition, or unbuckled seat belts. A short to ground prevents the circuit from functioning properly, which can cause the chime to not sound when needed or to stay on continuously. The chime request circuit typically operates using a reference voltage signal monitored by the module. When a short to ground occurs, the voltage drops below the expected threshold, and the module logs the fault code. Diagnosis requires checking the wiring between the door switch, BCM, and chime speaker, as well as ruling out faults in associated components.
1. Commonly Affected Makes
2. Most Common Causes
- Chime circuit wiring damaged by chafing, corrosion, or pinching causing contact with chassis ground
- Instrument cluster or BCM connector with bent pins, corrosion, or moisture
- Internal failure of the ICM or BCM causing incorrect circuit reading
- Door switch or open sensor with internal short to ground
- Aftermarket accessory installation interfering with the chime circuit
- Chime speaker or tone generator with coil shorted to ground
3. Symptoms You Will Notice
- Chime does not sound when expected (e.g., door open, key in ignition)
- Chime sounds continuously or intermittently without cause
4. Step-by-Step Diagnosis
Scan for additional codes and verify B1340 is present
Inspect chime circuit wiring for damage, corrosion, or shorts to ground
Check ICM and BCM connectors for bent pins, corrosion, or moisture
Test door switches and sensors for internal shorts to ground
Disconnect aftermarket accessories to rule out interference
If all else fails, test chime speaker for internal short and replace if faulty
5. Frequently Asked Questions
Is it safe to drive?▼
Yes, it is generally safe to drive with code B1340. The chime may not work properly, but the vehicle's essential functions remain unaffected. However, you may miss important alerts like door ajar or seatbelt reminders.
How much does it cost to fix?▼
Repair costs typically range from $100 to $300, depending on the cause. Simple wiring repairs may cost less, while replacing a BCM or ICM can be more expensive.