Body, generic

B0158 Ambient Air Temperature Sensor Circuit

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

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.

Likely causes

Sensor at the front bumper unplugged or connector damaged after front-end work
Thermistor in the outside air sensor open or shorted, often after stone impact
Signal or low reference wire to the cluster damaged

Symptoms

  • 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

Repair estimate

DifficultyMediumDIY possible
Parts and labour€20–150
Time0.3–1 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

ambient air temperature sensorinstrument clusterhvac control module

Related codes

B0159B0255

References: saabwisonline.com, saabwisonline.com, saabwisonline.com, static.nhtsa.gov.