B1602

B1602 is a Ford module-programming code that means the receiving module (PCM, BCM, IPC, or ABS) is reporting either a missing/invalid VIN in its memory or a checksum failure on its programming data. The module powered up, asked the network for its expected VIN, and either got no response, got a VIN that didn't match what it expected, or detected internal data corruption. Cheapest-first ladder: (1) Confirm the VIN matches across all modules using FORScan or IDS — if one module reports the wrong VIN, it's been swapped in from another vehicle or its memory has corrupted. (2) Check network communication on the HS-CAN and MS-CAN buses with a scope — if the PCM can't reach the BCM to confirm VIN handshake at key-on, B1602 sets even on a perfectly good module. (3) Re-flash / re-program the module with the correct As-Built data using FORScan (free for read, paid license for write) or Ford IDS at the dealer. (4) Verify the security access (key/PATS) is properly paired — a swapped PCM that hasn't been PATS-married to the body will throw B1602 alongside a no-start condition. Expensive-misdiagnosis caveat: B-codes for module programming/configuration almost never mean a bad module — they mean a missing or corrupted As-Built / FORScan / GM Tech-2 config file; before condemning a $400-$1000 module, attempt re-configuration with dealer scan tool first. A used PCM/BCM from a junkyard is a $50-$150 part that becomes a $0 fix once you load the correct As-Built data into it.

Vehicle-specific patterns: 2007-2014 Lincoln Navigator and Ford Expedition are the most common B1602 platform — used PCM swaps to address timing-chain-tensioner failures on the 5.4L 3V routinely throw B1602 because the donor PCM carries the donor vehicle's VIN, and without an As-Built reprogram the new PCM never matches the rest of the network. 2008-2012 Ford F-150 with the 5.4L or 6.2L throws B1602 after any module replacement that wasn't accompanied by a proper As-Built download — FORScan with a paid license is the independent-shop fix, IDS at the dealer is the OE fix. 2010-2014 Ford Edge/Flex/Taurus with EATC HVAC modules throws B1602 after a used-HVAC-head swap from a different VIN. 2005-2010 Mustang GT/Shelby with PCM tuning chips occasionally throws B1602 when the tune's checksum doesn't validate against the factory As-Built. Estimated repair: $90 (FORScan license + As-Built reprogram DIY) to $1,200 (dealer PCM replacement and PATS reprogram).