B1541

DTC B1541: Back-Up Power Supply Circuit Malfunction

Wiring Diagram










DTC Detecting Condition and Trouble Area





NOTE:

When checking DTC after connecting battery cable, be sure to turn ignition switch from OFF to ON and from ON to OFF at least once, or DTC B1541 will be detected.

DTC Troubleshooting

1.
Was "Air Conditioning System Check" performed?
YES -
Go to Step 2.
NO -
Go to Air Conditioning System Check Air Conditioning System Check:Auto A/C.

2. DTC check

Turn ignition switch to ON position for 20 sec. or more.
Ignition switch turned OFF and connect scan tool to DLC.
Turn ON ignition switch and check DTC.

Is there DTC B1541?
YES -
Go to Step 3.
NO -
Intermittent trouble. Check for intermittent referring to Intermittent and Poor Connection Inspection Intermittent and Poor Connection Inspection.

3. Battery voltage supply circuit check

Disconnect connector from HVAC control module with ignition switch turned OFF.
Check for proper connection to backup power supply circuit terminal of HVAC control module connector.
If OK, measure voltage between backup power supply circuit terminal of HVAC control module connector and vehicle body ground.

Is voltage 10 - 14 V?
YES -
Substitute a known-good HVAC control module and recheck.
NO -
Backup power supply circuit is open or shorted to ground.