B1359
Ignition Run/Acc Circuit Failure
Body Chassis/Safety Ignition Circuit 🟢 Low — Fix at next service
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What This Actually Means
In plain language — no jargon

Your vehicle's ignition switch circuit isn't sending the proper electrical signal to the engine control module. Think of it like a light switch that's not properly connected—the power is there, but the signal isn't getting through.

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Symptoms You May Notice
3 known symptoms for this code
Dashboard lights flicker or don't illuminate properly
Engine starts intermittently or fails to crank
Accessory power (radio, windows) works erratically
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Embedded Systems Insight
What the ECU/ECM is actually computing

The ECM monitors voltage on the ignition run/accessory circuit to ensure proper power delivery during startup and operation. It detects open circuits, shorts, or voltage drops that indicate wiring or switch failure.

Voltage & Parameter Thresholds

Parameter Normal Range Fault Condition
Ignition Run Voltage 12-14.5V during cranking/running Below 10V or above 16V, or erratic fluctuations
Circuit Continuity Continuous signal present at key positions Intermittent or missing signal at Run/Acc positions
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Diagnostic & DIY Fix Guide
Check these in order — from cheapest to most complex
1
Ignition switch contacts
Clean or replace the ignition switch if contacts are corroded or worn.
2
Battery terminals and ground cables
Inspect for corrosion, loose connections, and clean or tighten all battery connections.
3
Ignition switch wiring harness
Check for damaged, pinched, or corroded wires between the switch and ECM.