Ambient Air Temperature Sensor Failure
The vehicle's ambient air temperature sensor is malfunctioning.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The computer is designed to monitor outside air temperature via a sensor. When the sensor fails, it sends incorrect readings or no reading at all, which impacts fuel and air mixture decisions.
What the computer is actually seeing
The PCM expects a voltage signal that changes with temperature, typically from 0.5V (approximately -40°C) to 4.5V (approximately 125°C). If readings stay static or exceed this range, it triggers the fault code.
What a healthy reading looks like
Normal operation should show a voltage between 0.5V and 4.5V, corresponding to temperatures from -40°C to 125°C. An open circuit shows 0V, while a short circuit can show 5V.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Inspect the ambient air temperature sensor wiring and connector for damage or corrosion. Decision: If damaged, repair or replace the wiring/connector; if intact, proceed to step 2.
- 22. Measure the voltage at the sensor connector while the vehicle is running. Expected: 0.5V to 4.5V. Decision: If out of range, the sensor is likely faulty; if within range, check the PCM input.
- 33. If the sensor voltage is good, check the PCM for the expected input related to outdoor temperatures. Decision: If the PCM reacts correctly, the issue may be intermittent; if not, replace the PCM.
Common causes
- Faulty ambient air temperature sensor
- Wiring issues (frayed/corroded)
- Poor connector contacts
- Open or short circuit in the signal line
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code active?
Yes, but the vehicle's performance may be affected. It's a good idea to fix this soon to maintain optimal efficiency.
Will this code come back after clearing it?
If the underlying issue isn't resolved, it will likely return. Keep monitoring the sensor and wiring.
Why does this code appear with other codes?
If multiple sensors are affected, it might suggest a common wiring issue or PCM malfunction.
Working a real vehicle right now?
Let DiagCoach walk you through it live with your specific symptoms, vehicle, and what you've already checked.
Start guided diagnostic →