DTC B112A:16 [Advanced Keyless Entry And Push Button Start System]: Notes

WARNING: This page is about a different car, the 2009 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.

DETECTION CONDITION AND POSSIBLE CAUSE

DETECTION CONDITION	IG2 monitor input circuit voltage less than threshold (2.2-6.5 V ) is detected for 1 s , while IG2 relay output circuit is active
POSSIBLE CAUSE	A/C 10 A fuse malfunction Connector or terminal malfunction Short to ground in wiring harness between relay block terminal 1F and keyless control module terminal 4X Relay block malfunction Open circuit in wiring harness between relay block terminal 1F and keyless control module terminal 4X Keyless control module malfunction
Courtesy of MAZDA MOTORS CORP.