Code Definition

B1602 — PATS Received Invalid Format Of Key-Code From Ignition Key Transponder

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

About B1602

B1602 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.

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.

B1602 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 Ford Passive Anti Theft System (PATS) module energises the transponder chip in the ignition key through the antenna coil and reads back a digitally encoded ID stream that follows a specific bit pattern and length. DTC B1602 sets when the PATS transceiver receives a response from a transponder, but the data stream is malformed in its structure, for example the wrong number of bits, an invalid checksum, or a non Ford transponder protocol. This differs from B1601, where the format was valid but the ID did not match a stored key. B1602 typically points to electrical interference corrupting the...

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