Powertrain, generic · Fuel and air metering, auxiliary emission controls
P00D9 Ambient Air Temperature Sensor Circuit B
Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo
Ambient air temperature sensor B is a second, separate ambient temperature circuit in addition to sensor A. What the second measuring point is used for in a given vehicle could not be documented; the value may be wired directly to the control module or come over the data bus. Regulations require monitoring of such inputs because ambient temperature is often an enabling condition for other diagnostics. None of the manufacturer documents searched uses these codes; the explanation follows sensor A. P00D9: This is the general circuit fault or an invalid signal.
Likely causes
Sensor faulty (exposed to spray and stone chips)
Connector corroded or wiring damaged, often after front-end work
Module supplying the value over the data bus faulty
Control module faulty
Symptoms
- Wrong or missing outside temperature display
- Climate control regulates incorrectly
- Check engine light on (manufacturer-dependent)
Repair estimate
DifficultyEasyDIY possible
Parts and labour€50–150
Time0.3–1 h
Typical range across vehicles; the real cost depends on what the testing finds.
Parts involved
ambient air temperature sensor bambient air temperature sensor wiring
Related codes
References: law.cornell.edu, gsi.ext.gm.com, fordservicecontent.com.