B1357 — Ignition Run Circuit Short To Battery #

Note: The description for this code may vary depending on the vehicle manufacturer (OEM). Always refer to your specific vehicle service manual for the most accurate information.

• Ignition Run Circuit Shorted to Battery (Ford, Lincoln, Mercury)
• Ignition Switch Run Input Circuit High (GM, Chevrolet)
• Ignition ON/Run Circuit High Voltage (Chrysler, Jeep)

Summary of the B1357 Code #

The B1357 – Ignition Run Circuit Short To Battery diagnostic trouble code (DTC) indicates that the vehicle’s onboard diagnostics (OBD-II/EOBD) system has detected an electrical fault in the ignition run circuit. Specifically, the circuit is registering a voltage that suggests it is being shorted directly to battery voltage, which is higher than what the system expects during normal operation. This can cause erratic behavior in the ignition system and potentially affect other electrical systems powered during the “run” position. While the code itself is not always immediately dangerous, addressing it promptly is essential to avoid further damage or drivability issues. The actual label and meaning may slightly differ based on the OEM, but the core issue remains: there is an abnormal electrical path in the ignition run circuit.

Common Symptoms for Code B1357 #

A vehicle with a B1357 code may exhibit a range of symptoms, depending on the severity and the affected components. Typically, the car’s ignition system and associated electronics are the most impacted. Watch for these signs:

• Intermittent or non-functional ignition (vehicle may not start or may stall unexpectedly)
• Dashboard warning lights illuminated (such as the Check Engine Light or Service Engine Soon)
• Electrical accessories (radio, HVAC, power windows) not responding properly when the ignition is on
• Battery draining faster than normal
• Flickering or dimming dashboard lights

Likely Causes for Code B1357 #

The B1357 code most often results from issues in the wiring or components related to the ignition run circuit. Here’s a breakdown of the most frequent culprits, ranked by how commonly they occur:

1. Damaged wiring harness (insulation worn, pinched, or melted wires causing a short to battery)
2. Faulty ignition switch (internal contacts shorted or sticking in the run position)
3. Corroded or loose ignition circuit connectors
4. Aftermarket accessory installation tapping into the ignition circuit improperly
5. Failed relay or fuse associated with the ignition run circuit
6. Defective body control module (BCM) or engine control module (ECM), though less common

Step-by-Step Diagnostic for Code B1357 #

Diagnosing B1357 requires patience and a logical approach. Begin with the basics and work towards more complex possibilities. Here’s a proven step-by-step guide:

• Verify the code and clear it; see if it returns after cycling the ignition.
• Inspect the ignition run circuit wiring for visible damage, focusing on areas near moving parts or heat sources.
• Check all connectors in the ignition circuit for corrosion, bent pins, or poor fitment.
• Test the ignition switch operation; use a multimeter to confirm correct continuity and voltage at each position.
• Examine aftermarket accessory connections for signs of improper splicing into the ignition run wire.
• Check the appropriate fuses and relays for signs of overheating or damage.
• If all else checks out, test the BCM/ECM as per OEM procedure. Consider consulting a factory wiring diagram for precise pin locations and test points.

Possible Repairs for Code B1357 #

Resolving B1357 means correcting the abnormal electrical path in the ignition run circuit. Depending on your diagnostic findings, typical repairs include:

• Repairing or replacing damaged wiring in the ignition run circuit
• Replacing a faulty ignition switch
• Cleaning or replacing corroded connectors
• Correcting or removing any improper aftermarket accessory wiring
• Replacing a failed relay or fuse in the ignition circuit
• If necessary, replacing the BCM or ECM (only after confirming all other possibilities)

Can You Drive with Code B1357? #

Limited. While some vehicles may continue to operate with a B1357 code, it is not recommended to drive for extended periods. The risk of sudden stalling, failure to restart, or further electrical problems increases the longer the issue is ignored. In some cases, the vehicle may not start at all. Prompt diagnosis and repair are the safest choices.

Vehicles Most Commonly Affected by Code B1357 #

This code appears most frequently in vehicles from manufacturers that use detailed body control diagnostics, but it can be found in many models. Typically, it’s seen in:

• Ford (including Lincoln and Mercury models)
• General Motors (Chevrolet, GMC, Buick, Cadillac)
• Chrysler, Jeep, Dodge
• Some Japanese and European vehicles with advanced body modules

Common Mistakes & Best Practices for Code B1357 #

Misdiagnosis can lead to wasted time and money. Here are typical pitfalls and how to avoid them:

• Replacing the ignition switch without confirming the wiring is intact
• Overlooking aftermarket accessories as a source of shorts
• Ignoring signs of water intrusion or corrosion in connectors
• Not clearing the code after repairs to verify the fix
• Skipping the use of a factory wiring diagram for precise troubleshooting

FAQ Express: B1357 Code #

Curious about the B1357 code? Here are answers to the most common quick questions:

• Q: Will replacing the ignition switch always fix B1357?
  A: Not necessarily. While a failed ignition switch is common, the real cause can often be damaged wiring or a faulty connector. Always diagnose before replacing parts.
• Q: Can B1357 cause my car to stall while driving?
  A: Yes. A shorted ignition run circuit may interrupt power to essential systems, potentially resulting in unexpected stalling or even a no-start condition.