B1315 — Battery Saver Relay Coil Circuit Short To Battery #

Note: The code label may vary depending on the vehicle manufacturer.

• Ford: Battery Saver Relay Coil Circuit Short To Battery
• General Motors (GM): Battery Saver Relay Circuit High
• Chrysler: Battery Saver Relay Control Circuit High
• Hyundai/Kia: Battery Saver Relay Coil Short to B+

Summary of DTC B1315 #

DTC B1315 signals that the Battery Saver Relay Coil Circuit is experiencing a short to battery voltage. The battery saver relay is an electrical component designed to disconnect non-essential electrical loads (such as interior lights) after a set period, preserving battery life when the ignition is off. A “short to battery” means the relay coil circuit is unintentionally receiving continuous voltage, potentially keeping the relay energized when it shouldn’t be. This condition is usually detected by the Body Control Module (BCM), which monitors the relay’s operation. If not addressed, this code can gradually drain your battery and may be a symptom of deeper wiring or module issues.

Common Symptoms for Code B1315 #

Drivers and technicians may notice that some electrical accessories behave oddly or remain powered when they should not. The car might exhibit warning lights or alert messages related to battery or electrical load management. In some cases, these symptoms are subtle, only appearing after the vehicle has been parked for an extended period.

• Interior lights staying on after the vehicle is locked
• Battery drains overnight or more quickly than usual
• Warning lights or battery saver messages on the dashboard
• Relays audibly clicking or remaining active when ignition is off
• BCM-related error codes or intermittent electrical faults

Probable Causes for B1315 #

Several faults can trigger B1315, but some are more common than others. Understanding the likely causes helps prioritize diagnostics and avoid unnecessary part replacements. Here are the most frequent culprits, in order of likelihood:

1. Shorted wiring in the battery saver relay coil circuit (wire insulation damage, pinched or chafed harness)
2. Faulty battery saver relay (relay internally shorted or stuck closed)
3. Corroded or damaged relay socket causing voltage bleed
4. BCM fault (internal fault or failed output transistor)
5. Incorrectly installed aftermarket accessories drawing or sending voltage onto the relay circuit

Step-by-step Diagnosis for B1315 #

A systematic approach is key to pinpointing the root cause. Avoid jumping to conclusions or replacing parts blindly; instead, use the following step-by-step process:

• Confirm code B1315 is present using a scan tool and check for related codes.
• Inspect battery voltage and ensure it is within normal range (12.4–12.7V engine off).
• Locate the battery saver relay (refer to the OEM wiring diagram for exact location).
• Visual inspection: Examine relay, socket, and related wiring for signs of damage, corrosion, or aftermarket modifications.
• Remove the relay and check for continuity between relay coil terminals and battery voltage (shouldn’t see voltage with ignition off).
• Test circuit resistance between relay coil control and ground; look for short circuits to battery voltage using a multimeter.
• Substitute a known good relay if the relay is suspect.
• Monitor BCM command with a scan tool or test light to verify if the BCM is incorrectly energizing the relay.
• If all else checks out, suspect an internal BCM fault and follow OEM test procedures for BCM output diagnostics.

Possible Repairs for B1315 #

Once the root cause is found, repairs can be targeted and efficient. Always clear the code and retest after each repair step to ensure the issue is resolved.

• Repair or replace damaged wiring (repair insulation, reroute harness, or replace affected section)
• Replace faulty battery saver relay
• Clean or repair corroded relay socket
• Remove or correct aftermarket accessory wiring interfering with the circuit
• Replace BCM if confirmed faulty after all other steps

Is It Safe to Drive with B1315? #

Technically, you can drive with code B1315 present, as it rarely affects immediate vehicle safety or drivability. However, if the battery saver function is compromised, your battery may discharge overnight or after extended parking. If you notice repeated battery drain or electrical accessories that won’t turn off, park the vehicle safely and address the issue promptly to avoid being stranded with a dead battery.

Vehicles Most Commonly Affected by B1315 #

While any vehicle equipped with a battery saver relay can experience this code, certain makes and models are more frequently reported in service bulletins and forums. This often relates to BCM design, relay location, or wiring harness routing.

• Ford F-Series and Fusion (various years)
• Chevrolet Malibu, Impala, and Silverado
• Chrysler Town & Country, Dodge Caravan
• Hyundai Sonata, Kia Optima
• Lincoln MKZ and Navigator

Common Mistakes & Best Practices for B1315 Diagnosis #

Misdiagnosis is common with B1315, especially when technicians overlook simple visual checks or skip wiring inspection. Here’s how to avoid wasted time and parts:

• Don’t replace the BCM without first verifying wiring and relay condition
• Always inspect for aftermarket accessories or recent wiring work
• Use the correct OEM wiring diagram; circuit locations may vary by year/model
• Verify the relay’s integrity with a known good part before condemning modules
• Clear codes and retest after each repair step to confirm resolution

Quick FAQ on B1315 — Battery Saver Relay Coil Circuit Short To Battery #

Got more questions? Here are quick answers to the most common ones:

• Q: Can a weak battery trigger B1315?
  A: Not directly. B1315 points to a circuit short, not low battery voltage. However, a persistently drained battery may be a symptom.
• Q: Do I need a scan tool to diagnose B1315?
  A: A scan tool is helpful for confirming the code and BCM data, but a multimeter and wiring diagram are essential for a thorough diagnosis.
• Q: Will disconnecting the battery clear B1315?
  A: It may clear the code temporarily, but if the underlying fault is not fixed, the code will return.