Code Definition

B1845 — Ignition Tamper Circuit Failure

System: Body  |  Type: Manufacturer-Specific  |  Make: Ford

About B1845

B1845 is a manufacturer-specific body diagnostic trouble code recorded for Ford vehicles. It belongs to the B-prefix family of codes, which covers body, interior, airbag, or comfort-electronics faults.

When B1845 is stored, the module has detected an electrical-circuit fault in the wiring, connector, or driver associated with the named component.

Scanning & clearing: Body (B) codes are often stored in the body control module, airbag module, or climate module. A basic OBD-II tool usually will not read body codes — an enhanced or OEM-level scan tool is typically required.

B1845 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

The B1845 fault code is set by the Body Control Module (BCM) or Generic Electronic Module (GEM) when it detects an electrical failure on the ignition tamper switch circuit. The ignition tamper sensor is a security input mounted at the steering column that signals the security module if the ignition lock cylinder has been forcibly removed or attacked. The module monitors the tamper switch circuit for open, short to ground, or short to power conditions, and stores B1845 when the circuit state is outside expected limits. The driver may notice the theft system indicator behaving abnormally, a no s...

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