B0158Ambient Air Temperature Sensor Circuit
- Generic OBD-II code · Body
- How the car detects it
- Although B0158 is absent from the publicly available J2012 lists, General Motors and Saab use it with exactly this meaning. In the 2011 Saab 9-4X the instrument cluster reads the outside air sensor and stores B0158 02 when the signal implies more than 88 °C, B0158 05 below −40 °C; the display then shows dashes. Saab 9-3 manuals place it in the body module: under 0.25 V means short to ground, above 5 V means open or short to supply, and the last known value is kept. GM bulletin PIC5656F (LaCrosse 2010–13, Verano 2012–16, Malibu 2013–16, Cascada 2017) links B0158 to a missing outside temperature and an HVAC display stuck in Celsius, and starts with the sensor plug and circuits 61 and 636.
- What you may notice
- Outside temperature display missing or showing dashes
- Automatic climate control works with a stored or default temperature
- On some GM models the HVAC display switches to Celsius
- Likely causes
- LikelySensor at the front bumper unplugged or connector damaged after front-end work
- PossibleThermistor in the outside air sensor open or shorted, often after stone impact
- PossibleSignal or low reference wire to the cluster damaged
- Repair
- Medium · Often possible to do yourself.Typical cost: €20 – €150
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.