2015 Hyundai Sonata Hybrid Limited – No Start With Battery Temperature Sensor Code P1B03
- Aug 16
- 1 min read
CUSTOMER CONCERN
The vehicle will not start, hybrid-battery state of charge is low, and auxiliary-battery-temperature-sensor DTC P1B03 returns immediately after clearing.
CAUSE
The auxiliary-battery temperature-sensor connector was left unplugged after battery replacement, opening the sensor circuit and blocking a forced engine start.
CORRECTION
Reconnect and secure the auxiliary-battery temperature-sensor connector, clear DTC P1B03, use the scan tool to command an engine start when state of charge permits, and verify the generator charges the hybrid battery.