B1310 — Power Door Unlock Circuit Failure

What are the symptoms of B1310?

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 B1310 clear itself?

Sometimes B1310 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 B1310?

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.

Is it safe to drive with B1310?

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 B1310 myself?

Start with a scan: confirm B1310, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the power door unlock circuit, and verify the suspect component against live data before buying parts.

The engine control module keeps a constant eye on the body's electrical circuits. When it recognizes an open, short, or other abnormality in the power door unlock circuit, it logs OBD2 code B1310. This falls squarely in the body-chassis category, meaning the engine itself usually keeps running without any hesitation or stumbling.

Power door locks operate through a straightforward chain: you flip a switch, the body control module receives that signal, and it then activates small electric motors inside each door to lock or unlock. B1310 triggers when the module stops getting the response it expects from that circuit. The PCM won't turn on the check engine light after a single bad reading—it waits for the fault to show up consistently under specific operating conditions. That freeze frame data stored alongside B1310 is gold: it records engine load, RPM, coolant temperature, and vehicle speed the exact moment the problem appeared. Use those numbers to recreate the failure during diagnosis.

Common Symptoms of B1310

• The check engine light or dedicated body warning indicator illuminates on the dash
• One or more door locks fail to respond to the switch, or operate only sporadically
• The malfunction has zero effect on engine performance, fuel economy, or transmission behavior
• Other body functions sharing the same circuit—windows, interior lighting, or wipers—may act up as well
• The problem often worsens in wet or humid weather when moisture gets into connectors

Common Causes of B1310

• Worn-out door lock switches or failed door latch actuators — by far the most frequent offender
• Broken or chafed wiring inside door jambs, where flexing breaks conductors over time
• Corroded, pushed-back, or otherwise poor electrical connectors in the door wiring harness
• Faulty body control module that misinterprets or ignores lock commands
• Blown fuse or malfunctioning relay dedicated to the door lock circuit
• Water intrusion into door panels damaging both connectors and wire insulation

How to Diagnose B1310

1. Hook up an OBD2 scanner and verify B1310 is stored in the module's memory, then record the freeze frame data before clearing anything.
2. Scan for any related diagnostic trouble codes — body system codes often travel in pairs and point toward the actual root cause rather than just the symptom.
3. Pull up manufacturer technical service bulletins for your specific vehicle using the VIN search on the OEM site or nhtsa.gov; many B0xxx codes have documented factory fixes or software calibrations.
4. Visually trace the door lock wiring harness, paying special attention to the door jamb areas where wires flex every time you open and close the door.
5. Actuate the door lock switch while monitoring switch status and motor draw in the scanner's live data stream.
6. Clear B1310, then drive through a complete drive cycle that replicates the freeze frame conditions, and confirm the code does not set again.

Repair Options and Costs

Start troubleshooting from the least expensive components before touching anything complicated:

• Replace door lock switch or actuator motor — $120–$450
• Repair damaged wiring or connectors — $80–$250
• BCM repair or full replacement — $300–$900

How Much Does It Cost to Fix B1310?

Your final invoice hinges entirely on what component caused the fault. Here is how typical B1310 scenarios break down at independent shop labor rates in the United States:

• Door lock switch or actuator replacement: $120–$450
• Wiring harness or connector repair: $80–$250
• Body control module repair or replacement: $300–$900

Across all scenarios, fixing B1310 generally runs between $80 and $900. Spend time diagnosing before spending money on parts—an accurate diagnosis is always cheaper than guessing wrong on a $900 BCM.

Can You Drive with B1310?

Yes, most of the time. Body electrical faults do not directly compromise engine operation, so drivability stays intact. That said, a failed central locking system can leave your car unsecured, and if the fault also affects headlights or wipers, hazardous conditions can develop quickly in bad weather. Get it diagnosed and repaired at your earliest convenience.

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