B1355
Ignition Run Circuit Failure
Body Ignition System Ignition Power Supply 🟢 Low — Fix at next service
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What This Actually Means
In plain language — no jargon

Your vehicle's ignition system isn't receiving proper electrical power during the run phase, similar to a light switch that won't stay in the 'on' position. This prevents the engine from running or causes it to stall unexpectedly.

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Symptoms You May Notice
3 known symptoms for this code
Engine cranks but won't start or start then immediately stalls
Instrument cluster lights flicker or dim during starting
No power to fuel pump or ignition coils during engine run
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Embedded Systems Insight
What the ECU/ECM is actually computing

The ECU monitors voltage supply on the ignition run circuit during engine operation, expecting stable 12V+ power to fuel and ignition systems. When voltage drops below threshold or signal is lost, the ECU detects a circuit failure and sets the code.

Voltage & Parameter Thresholds

Parameter Normal Range Fault Condition
Ignition Run Voltage 11.5V - 14.5V during engine run Below 10.5V or open circuit detected
Voltage Stability Steady supply with minimal fluctuation Voltage dropout or intermittent signal loss
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Diagnostic & DIY Fix Guide
Check these in order — from cheapest to most complex
1
Battery terminals and connectors
Clean corrosion from battery posts and ensure all ignition-related connectors are tight and free of oxidation.
2
Ignition switch
Test continuity through the ignition switch in the run position; replace if contacts are worn or stuck.
3
Main fuses and relay (ignition/run circuit)
Inspect and test fuse links and ignition relays for continuity; replace blown fuses or faulty relays.