DTC P1603: Battery Backup Line Malfunction

TECHNICAL DESCRIPTION
• The PCM is checks the open circuit of battery backup line.
NOTE: When the system detects an open circuit in the battery backup line, it makes 1 failure judgment of other diagnostic trouble codes (DTCs).
DESCRIPTIONS OF MONITOR METHODS
Battery backup line voltage is under specified value.
MONITOR EXECUTION
Continuous
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)

Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
• Not applicable

Sensor (The sensor below is determined to be normal)
• Not applicable
LOGIC FLOW CHART

Check Conditions
Starting sequence was completed.
Battery positive voltage is higher than 10 volts.

Judgement Criteria
• Battery backup line voltage has continued to be 6 volts or lower for 2 seconds.
OBD-II DRIVE CYCLE PATTERN
None.
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are: )
• Open or shorted battery backup line, harness damage or connector damage.
• PCM failed.
NOTE: When the engine is started with the IOD or storage connector disconnected, the PCM judges that an open circuit has occurred in the battery backup line. Consequently, the service engine soon/malfunction indicator lamp illuminates and the DTC is stored in memory.