B0159 code meaning
Outside Temperature Sensor Range/Performance
What B0159 means
No public J2012 source lists B0159. General Motors uses it: bulletin PIP5094 from 2013 lists B0159 among its service information keywords, though without a description, so no public GM text states the exact fault logic. Its neighbour B0158 is GM's outside air sensor circuit code. The sensor is an NTC thermistor behind the front bumper; per the 2011 Saab 9-5 manual the cluster supplies 5 V, sees high resistance and voltage when it is cold and low values when it is hot. A range/performance fault, unlike B0158, concerns a signal that stays inside the electrical limits but is implausible, for example frozen at one value or far from what other temperatures suggest. Result: wrong outside reading.
B0159 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.3 to 1 hours
- Clears after repairWhen cleared with a scanner
Symptoms of B0159
- Displayed outside temperature clearly too high or too low
- Climate control or A/C compressor behaves oddly because of the wrong outside value
Common causes of B0159
- Most likelyOutside air sensor drifted or slow to react, giving plausible but wrong values
- PossibleSensor mounted where engine or road heat reaches it, e.g. after a bumper repair
- Less likelyCorroded contact adding resistance and shifting the reading
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Outside temperature sensorHvac control module
What each part of B0159 means
| B | Body system: airbags, seat belts, power seats, lights and climate control. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 59 | The exact fault in that area. |
What to do next
- Note B0159 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about B0159
What does B0159 mean?
B0159 means "Outside Temperature Sensor Range/Performance". No public J2012 source lists B0159. It is a generic code, so it means the same on every make.
Is it safe to drive with B0159?
B0159 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will B0159 fail an emissions test?
B0159 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is B0159 to fix?
Difficulty: medium. A typical repair takes 0.3 to 1 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will B0159 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.