What it means
The intake air temperature sensor 3 circuit signal on bank 1 is intermittent or erratic.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Intake air temperature sensor 3 on bank 1 sends an air temperature signal to the engine control module. This code sets when that signal on bank 1 repeatedly drops out or changes unpredictably, often as a loose connection or vibrating harness interrupts contact.
Common causes
Most likely first.
- Connector loose or corroded
- Connector with intermittent contact under vibration
- Harness routed against vibrating component
Symptoms
- Check-engine light on
- Reduced engine performance or power
- Intermittent changes in engine performance
How to diagnose it
- Record freeze-frame data and watch bank 1 sensor 3 live data for sudden jumps or dropouts while comparing it with other temperature readings.
- Inspect the bank 1 sensor 3 connector for looseness, corrosion, backed-out pins, or damaged locking tabs.
- Trace the sensor harness and look for rubbing against a vibrating component, chafed insulation, or an unsupported section.
- With live data displayed, gently move the connector and harness to see whether the reading changes when the fault is reproduced.
- Check connector terminal fit and circuit continuity during harness movement, then test the sensor against the manufacturer's specification.
Common fixes
- Secure the loose bank 1 sensor 3 connector and harness.
- Clean corroded terminals or replace damaged connector pins.
- Reroute and secure the harness away from vibrating or rubbing components.
- Replace the sensor if its output remains erratic with sound wiring and connections.
Can I keep driving?
If performance changes are brief and the engine otherwise runs normally, drive gently and arrange a prompt check. Avoid long trips if power drops unpredictably, since the intermittent temperature signal can cause inconsistent engine response.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.