Code
B1494
FIAT
B — Body
Ignition cylinder sensor short to ground
AI status
Completed
Completed
100%
Causes
- Damaged or chafed wiring that contacts chassis ground
- Corroded or pushed-back connector pins
- Faulty ignition cylinder / ignition switch sensor
- Poor ground or short inside steering column
- Faulty body control/immobilizer module input circuit
Symptoms
- No crank or no start condition
- Immobilizer or security warning lamp illuminated
- Intermittent inability to start or recognition of key
- Starter operates erratically or only with key held a certain way
- Possible loss of other steering-column electrical functions
What to check
- Read freeze frame and live data with a diagnostic scanner; record fault and status
- Inspect ignition cylinder/steering column connectors for corrosion, bent pins, moisture
- Visually inspect wiring harness for chafing where it passes through the column and dash
- Measure voltage at the sensor connector with key in proper position
- Check for related fault codes in immobilizer/body modules and engine control unit
Signal parameters
- Reference supply typically 5 V (or vehicle-specific reference); check factory data
- Normal sensor signal: toggles between near-reference and low depending on switch position
- Fault condition (short to ground): sensor signal close to 0 V (low impedance to ground)
- Open-circuit condition: signal may be floating or pulled up to reference voltage
- Expected circuit resistance: low ohms to reference or high/infinite if open — consult wiring diagram
Diagnostic algorithm
- Use a scanner to confirm B1494 active and note related codes; clear and attempt to reproduce.
- Visually inspect ignition cylinder area, connectors and harness for physical damage, corrosion or moisture.
- With ignition OFF, disconnect the sensor/ignition cylinder connector and inspect pins for damage or pushed-back terminals.
- Measure continuity from the sensor signal pin to chassis ground; a direct short (near 0 ohms) indicates a short to ground.
- With harness disconnected, check voltage on the vehicle-side connector with ignition ON: verify reference supply present and signal circuit not hard-grounded.
- Wiggle the harness and column while monitoring signal and scanner live data to find intermittent shorts.
- If wiring is shorted, trace and repair damaged section or replace harness; if wiring OK and sensor pins shorted internally, replace ignition cylinder sensor/switch assembly.
- If wiring and sensor check OK but fault remains, inspect/replace body control or immobilizer module input fuse/connector and consider module diagnostics with factory tools.
- After repair, clear codes and perform multiple start cycles to verify fault does not return.
Likely causes
- Wire insulation worn where wiring harness passes through steering column
- Connector pinned to ground or foreign material in connector
- Ignition cylinder sensor internal short or water ingress
- Aftermarket alarm/electrical work changed wiring routing
- Intermittent short caused by a broken conductor contacting metal
Fault status
Status
Ignition cylinder sensor: short to ground detected on sensor circuit. Low voltage at input reported by control module.
Repair difficulty: Medium
Diagnostic time: 0.5-2 hours
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