B1355 — Ignition Run Circuit Failure #

Note: The description for code B1355 may vary depending on the vehicle manufacturer. Always consult your OEM (Original Equipment Manufacturer) service information for the most accurate definition.

• Ignition Run Circuit Failure (General/Generic)
• Ignition Run Circuit Open (Ford)
• Ignition Switch Run Circuit Fault (GM)
• Ignition ON/Run Signal Malfunction (Toyota/Lexus)

Summary of Code B1355 #

B1355 is a diagnostic trouble code (DTC) that points to a problem with the ignition run circuit—the electrical path that provides power to vital vehicle systems when the ignition switch is in the “RUN” position. If your vehicle’s onboard diagnostics (OBD-II/EOBD) system detects an abnormal voltage, open, or short in this circuit, it will trigger B1355. This code is most often associated with issues in the wiring, ignition switch, or related relays and modules. Ignoring this code can lead to no-start conditions or sudden stalling, making it crucial to address promptly. While it may sound technical, with a systematic approach, even novice DIYers can grasp the basics of diagnosing and resolving this issue.

Frequent Symptoms for Code B1355 #

A vehicle experiencing a B1355 code will often display clear signs that something is amiss with the ignition run circuit. Here’s what you might notice:

• Engine won’t start (no crank or crank but no start)
• Intermittent stalling—the engine may die unexpectedly while driving or idling
• Dash warning lights flicker or remain on (especially the security, battery, or check engine lights)
• No power to accessories (radio, HVAC, windows) when key is in “RUN”
• Clicking sounds from under the dash or fuse box

Probable Causes for Code B1355 #

The B1355 code is most commonly triggered by issues related to the ignition switch and its associated wiring. However, several other culprits could be at play. Here are the most frequent causes, from most to least likely:

1. Faulty ignition switch—worn contacts or internal failure
2. Open or shorted wiring in the ignition run circuit
3. Loose, corroded, or damaged connectors at the ignition switch or related modules
4. Failed ignition relay (sometimes called the run/crank relay)
5. Blown fuse in the ignition circuit
6. Faulty body control module (BCM) or powertrain control module (PCM)

Step-By-Step Diagnostic for Code B1355 #

Diagnosing B1355 requires methodical checks to pinpoint the root cause. Here’s a step-by-step approach tailored for both DIYers and professional techs:

1. Check for other DTCs—some may provide helpful clues or indicate related issues.
2. Visually inspect the ignition switch and its harness for signs of damage, wear, or corrosion.
3. Test the battery voltage and ensure all connections are tight and clean.
4. Using a wiring diagram, trace the ignition run circuit from the switch through any relays and fuses.
5. With a multimeter, check for continuity in the ignition run wire(s); look for opens or shorts to ground.
6. Test the ignition switch output when in the “RUN” position—verify proper voltage is present.
7. Inspect the ignition relay: test for proper operation and replace if malfunctioning.
8. Check relevant fuses; replace any that are blown, but always investigate why a fuse failed.
9. If all hardware checks out, consider scanning/diagnosing the BCM or PCM for internal faults.

Possible Repairs for Code B1355 #

Once the cause has been isolated, repairs for B1355 are often straightforward but must be performed with care. Here are typical solutions, matched to the likely causes:

• Replace faulty ignition switch (if internal contacts are worn or circuit is open)
• Repair or replace damaged wiring in the ignition run circuit
• Clean or tighten corroded connectors at the switch, relay, or BCM/PCM
• Replace defective ignition relay
• Replace blown fuse—only after addressing the underlying issue
• Repair or replace faulty BCM/PCM (rare, but possible after other avenues are exhausted)

Is It Safe to Drive with Code B1355? #

No, it is not recommended to drive with an active B1355 code. Since this code affects the ignition run circuit, it can lead to sudden engine shutdowns or prevent the engine from starting. This poses safety risks, especially if the vehicle stalls in traffic or fails to restart in an emergency. Address the code before operating the vehicle on public roads.

Vehicles Most Commonly Affected by Code B1355 #

While B1355 can appear in various makes and models, it is most frequently reported in vehicles from manufacturers that use similar ignition circuit designs. Here are some of the most commonly affected:

• Ford (especially late 90s and early 2000s models)
• General Motors (Chevrolet, GMC, Cadillac, Buick)
• Toyota and Lexus (certain models with advanced security systems)
• Honda and Acura (occasionally, often linked to relay issues)
• Chrysler, Dodge, and Jeep (models with complex ignition modules)

Common Mistakes & Best Practices for Code B1355 #

Misdiagnosis can waste time and money. Here are frequent pitfalls—and tips to avoid them—when dealing with B1355:

• Replacing the ignition switch without testing wiring or relays first
• Ignoring connector corrosion, especially in humid climates
• Overlooking blown fuses as a symptom rather than the root cause
• Skipping a thorough visual inspection and going straight to module replacement
• Not consulting the OEM wiring diagram for the specific vehicle

Express FAQ for Code B1355 #

Still have questions? Here are quick answers to what most drivers and technicians ask about B1355:

• Q: Will clearing the code with a scanner fix the problem?
  A: No. The code will return unless the underlying fault is repaired.
• Q: Can a weak battery trigger B1355?

A: Indirectly, yes. Low battery voltage can cause erratic ignition circuit readings, but a good battery alone won’t resolve a true circuit fault.

• Q: Is this a common DIY repair?

A: Many ignition circuit repairs are within DIY reach, especially if caused by a blown fuse or minor wiring issue. However, complex wiring or module faults may require professional tools and expertise.