DTC U3004:12 [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	ACC relay output circuit voltage higher than threshold (2.2-6.5 V ) is detected for 1 s , while the circuit is not active
POSSIBLE CAUSE	Connector or terminal malfunction Short to power supply in wiring harness between relay block terminal 2E and keyless control module terminal 4F Relay block malfunction Keyless control module malfunction
Courtesy of MAZDA MOTORS CORP.