What Does B1493 Mean?
This code indicates the Body Control Module (BCM) has detected that the ignition cylinder sensor circuit is shorted directly to battery voltage instead of receiving the proper ground or signal voltage. The ignition cylinder sensor monitors key position and communicates with the vehicle's anti-theft and starting systems. This short circuit condition prevents the BCM from receiving accurate ignition switch position information, which can affect starting, accessory power distribution, and theft deterrent functions.
Safety Warning
Vehicle may not start, may stall unexpectedly, or anti-theft system may activate preventing operation. Driving is not recommended as the vehicle may shut down without warning or fail to restart after being turned off. Immediate repair is required to restore normal operation.
Common Causes
40%
Damaged or chafed wiring harness between ignition cylinder sensor and BCM creating short to battery voltage
30%
Failed ignition cylinder sensor with internal short circuit to power
20%
Corroded or damaged connector pins at ignition cylinder sensor causing cross-circuit short
10%
Water intrusion or moisture in ignition cylinder sensor assembly causing electrical short
Diagnostic Steps
1
Step 1: Perform visual inspection of ignition cylinder sensor connector and wiring harness at steering column for obvious damage, chafing, pinched wires, corrosion, or moisture. Check connector pins for proper seating and corrosion.
2
Step 2: Using a digital multimeter, disconnect the ignition cylinder sensor connector and measure resistance between the sensor signal wire and battery positive at the BCM side of the harness with key off - should read infinite resistance (open circuit). Any continuity indicates a short to battery voltage in the wiring.
3
Step 3: If wiring tests normal, measure resistance across the ignition cylinder sensor terminals with sensor disconnected - refer to manufacturer specifications but typically should show specific resistance values for different key positions. Out-of-spec readings or direct continuity to power pin indicates failed sensor.
4
Step 4: Inspect steering column area thoroughly for any aftermarket installations, modifications, or recent repair work that may have damaged wiring. Remove column covers if necessary to trace entire harness path for damage.
5
Step 5: After repair (sensor replacement or wiring repair), clear codes, cycle ignition through all positions multiple times, and verify proper sensor operation. Monitor for code return and confirm all ignition position-dependent functions (accessories, crank, run) operate correctly.
Estimated Repair Cost
$150 - $650
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected that the ignition cylinder sensor circuit is shorted directly to battery voltage instead of receiving the proper ground or signal voltage. The ignition cylinder sensor monitors key position and communicates with the vehicle's anti-theft ...
The most common cause of B1493 (Ignition Cylinder Sensor Battery Short) is: Damaged or chafed wiring harness between ignition cylinder sensor and BCM creating short to battery voltage
Typical repair costs for B1493 range from $150 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle may not start, may stall unexpectedly, or anti-theft system may activate preventing operation. Driving is not recommended as the vehicle may shut down without warning or fail to restart after being turned off. Immediate repair is required to restore normal operation.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1493 to identify the root cause.
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Quick Info
Category
Body
System
Body Control / Anti-Theft / Ignition System
Difficulty
Type
Manufacturer
Recommended Tools
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