DTC P0480:00: Notes

DTC P0480:00	Cooling fan relay No. 1 control circuit malfunction
DETECTION CONDITION	The PCM monitors the cooling fan relay No. 1 control signal voltage and current. If the following conditions are met, the PCM determines that there is the cooling fan relay No. 1 control circuit problem. The PCM turns the cooling fan relay No. 1 off, but the voltage of the cooling fan relay No. 1 control signal remains low. The PCM turns the cooling fan relay No. 1 on, but the current of the cooling fan relay No. 1 control signal remains high. Diagnostic support note This is a continuous monitor (other). The check engine light does not illuminate. FREEZE FRAME DATA (Mode 2)/Snapshot data is not available. The DTC is stored in the PCM memory.
FAIL-SAFE FUNCTION	-
POSSIBLE CAUSE	Cooling fan relay No. 1 malfunction Short to ground or open circuit in cooling fan relay No. 1 power supply circuit Short to ground in wiring harness between battery positive terminal and cooling fan relay No. 1 terminal E Open circuit in wiring harness between battery positive terminal and cooling fan relay No. 1 terminal E Short to ground in wiring harness between cooling fan relay No. 1 terminal A and PCM terminal 1U PCM connector or terminals malfunction Short to power supply in wiring harness between cooling fan relay No. 1 terminal A and PCM terminal 1U Open circuit in wiring harness between cooling fan relay No. 1 terminal A and PCM terminal 1U PCM malfunction
Courtesy of MAZDA MOTORS CORP.