What it means
Same as P242E on bank 2 sensor 4. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Bank 2 sensor 4 monitors exhaust gas temperature at its position in the exhaust, and its changing signal helps the control module manage emissions functions. P2477 means that signal from this specific sensor is intermittent or erratic, often because vibration disrupts a connector contact or moves a poorly routed harness.
Common causes
Most likely first.
- Intermittent contact at connector
- Connector with intermittent contact under vibration
- Harness routed against vibrating component
Symptoms
- Check-engine light on
How to diagnose it
- Save freeze-frame data and review bank 2 sensor 4 live readings for sudden jumps or dropouts compared with nearby exhaust temperature readings.
- With the exhaust cool, inspect sensor 4's connector for loose, corroded, or pushed-back pins and check its harness where it passes vibrating or hot components.
- With live data displayed, gently wiggle the bank 2 sensor 4 connector and harness to see whether the reading becomes erratic.
- Inspect the harness routing and clips for contact with a vibrating component, and check the circuit for intermittent continuity while moving the harness.
- If the wiring and connector remain stable, test bank 2 sensor 4 against the manufacturer's specification.
Common fixes
- Secure the bank 2 sensor 4 connector and repair loose or corroded terminals.
- Repair damaged wiring and add or restore harness supports to prevent vibration and rubbing.
- Reroute the harness away from the vibrating component or hot exhaust surfaces.
- Replace bank 2 sensor 4 if it produces an intermittent signal during specified testing.
Can I keep driving?
If the vehicle runs normally, short necessary trips are generally reasonable, but arrange diagnosis soon because an unstable reading can disrupt emissions monitoring. Stop if the check-engine light flashes or the vehicle develops a serious loss of power.
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.