What it means
The control or supply line to the electric catalyst heater on bank 2 is shorted to ground or measures below the expected voltage when the heater is commanded on.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The bank 2 catalyst heater circuit powers or controls the heater for the catalytic converter on bank 2. When the heater is commanded on, the control module detects voltage below the expected level; a short to ground, an internally shorted heater, or a poor connection can cause the low reading.
Common causes
Most likely first.
- Control line shorted to ground
- Heater element internally shorted
- Connector pins corroded - high contact resistance
Symptoms
- Check engine light on
- Possible increase in cold-start emissions
How to diagnose it
- Save freeze-frame data and confirm when the bank 2 heater was commanded on and the low-circuit fault was detected.
- Power down the system as directed by the manufacturer, then inspect bank 2 heater wiring and connector pins for damage, corrosion, moisture, or contact with ground.
- Check the bank 2 heater circuit for a short to ground using the manufacturer's isolation and test procedure.
- Measure voltage drop across the bank 2 heater connections under the specified test conditions and compare with the manufacturer's specification.
- If the wiring and connectors pass, test the bank 2 heater element for an internal short using the manufacturer's procedure.
Common fixes
- Clean and secure corroded or loose bank 2 heater connector pins.
- Repair a bank 2 heater control or supply wire shorted to ground.
- Repair damaged bank 2 heater wiring.
- Replace the bank 2 heater if it is internally shorted.
Can I keep driving?
This fault usually affects cold-start emissions rather than normal engine operation, but the warning light may remain on and the vehicle may fail an emissions inspection. Arrange diagnosis soon; take extra care around high-voltage components on hybrid vehicles.
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.