What it means
Catalyst temperature sensor at bank 2 sensor 2 below lower plausibility — short to ground. 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
The catalyst temperature sensor at bank 2, sensor 2 monitors exhaust catalyst temperature on the engine’s second bank. P043C sets when its signal is lower than the control module considers plausible, commonly because the signal circuit is shorted to ground or its connection has excessive resistance.
Common causes
Most likely first.
- Short to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
Symptoms
- Check engine light on
- Failed emissions inspection
- Possibly slightly increased fuel consumption
- Sulfur (rotten egg) smell from exhaust under load
How to diagnose it
- Confirm P043C and record freeze-frame data, then check whether the bank 2 sensor 2 live reading is abnormally low or fixed.
- With the exhaust cool, inspect that sensor's connector seals and pins for water, corrosion, pin push-back, or a loose fit.
- Trace the bank 2 sensor 2 harness where it passes near hot exhaust or moving parts and look for insulation worn through to ground.
- With the code active, gently move the accessible harness while watching live data to see whether the reading changes, taking care to keep clear of hot or moving parts.
- Use the wiring diagram to check the signal for a short to ground and verify terminal contact, then test the sensor against the manufacturer's specification.
Common fixes
- Dry and reconnect the bank 2 sensor 2 connector if moisture or poor seating is found.
- Repair chafed insulation or damaged wiring in the sensor signal circuit.
- Replace corroded or pushed-back terminals and restore the connector seal.
- Replace the sensor if the signal remains low with a verified, intact circuit.
Can I keep driving?
A low sensor signal usually does not cause limp mode, but emissions monitoring may be unreliable and the vehicle may fail inspection. Avoid heavy-load driving if a sulfur smell develops, and repair the wiring fault promptly to prevent it recurring.
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.