Code
B1492
Other
B — Body
Ignition Cylinder Sensor Open Circuit
AI status
Completed
Completed
100%
Causes
- Broken or disconnected wiring in ignition cylinder sensor circuit
- Corroded or loose connector at ignition cylinder or control module
- Failed ignition cylinder sensor or ignition switch assembly
- Blown fuse or poor power/ground to sensor circuit
- Module input fault or software/communication issue
- Water intrusion or mechanical damage to the steering column
Symptoms
- Engine will not crank or start intermittently
- No accessory or ignition power in some key positions
- Steering lock or immobilizer indicator illuminated
- No change in ignition switch position reported by scan tool
- Intermittent loss of electrical functions tied to ignition position
What to check
- Read stored DTCs and freeze-frame data with a scan tool; record related codes
- Verify battery voltage (12V nominal) to rule out low-voltage artifacts
- Visually inspect ignition cylinder/switch connector and harness for damage or corrosion
- Check related fuses and power/ground circuits
- Backprobe the sensor connector while operating the key to observe signal
- Wiggle test harness while monitoring signal to look for intermittent opens
Signal parameters
- Reference voltage: typically a switched 12V or 5V reference (manufacturer dependent) present at harness connector with key in proper position
- Ground: good continuity to chassis ground
- Sensor output: change of voltage or switch closure when key moved between OFF/ACC/ON/START
- Open-circuit condition: infinite resistance (OL) between sensor signal pin and module input or no change in voltage with key movement
Diagnostic algorithm
- Retrieve B1492 and any related codes. Note key position and engine state when code set.
- Confirm battery voltage is stable. Low voltage can cause spurious faults.
- Perform visual inspection of ignition cylinder, connector, and wiring for damage, corrosion, or water intrusion.
- Check fuses and main power/ground circuits associated with ignition switch assembly.
- Backprobe the ignition cylinder sensor connector. With key operated through positions, verify reference voltage, signal output, and ground continuity. Compare to expected values in manufacturer data.
- If no signal, test continuity between the sensor connector and the controlling module input. Repair any open or high-resistance wiring or connector issues.
- If wiring and connectors are good, replace the ignition cylinder/ignition switch assembly or sensor as per manufacturer procedure.
- After repair or replacement, clear codes and verify proper operation. Re-test by cycling the key several times and check for reappearance of the code.
- If code returns with correct wiring and sensor, check module inputs and CAN/communication for faults; consult manufacturer service information for module reprogramming or calibration requirements.
Likely causes
- Open wire or broken conductor between ignition cylinder sensor and body/control module
- Poor connector pin contact (corrosion, bent pin, pushed out terminal)
- Failed ignition cylinder position sensor inside ignition switch assembly
- Missing reference voltage or ground due to a blown fuse or bad splice
Fault status
Status
Ignition Cylinder Sensor Open Circuit — control module detects no continuity or missing signal from ignition cylinder sensor circuit.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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