Applicable Systems
OBD-II
Symptoms
The A/F sensor heater for bank 1 sensor 1 is drawing excessive current.
Possible Causes
- A/F sensor heater element shorted
- Wiring harness shorted to power
- Sensor connector damaged
- ECM heater driver shorted
- Heater circuit short
Troubleshooting Steps
- Step 1: Connect an OBD-II scan tool and read all stored DTCs and freeze frame data
All DTCs and freeze frame data are retrieved - Step 2: Inspect the related sensor or actuator wiring for damage, corrosion, or loose connections
Wiring and connectors are in good condition - Step 3: Use a digital multimeter to check sensor voltage, resistance, and reference signals per manufacturer specifications
Values are within specified range - Step 4: Perform component-level testing of the suspected sensor or actuator
Component passes or fails definitively - Step 5: Clear codes and road test to verify repair
Code does not return and system operates normally
How to Reset
To reset code P1412: 1) Repair the underlying fault. 2) Use an OBD-II scan tool to clear the DTC. 3) Perform a drive cycle.
Frequently Asked Questions
- Q: What does OBD-II code P1412 mean?
Code P1412 indicates: Air/Fuel Ratio Sensor Bank 1 Sensor 1 Heater Circuit High. This is a Toyota manufacturer-specific diagnostic trouble code.
- Q: Is code P1412 serious?
Severity: Major. Service as needed.
- Q: How do I fix code P1412?
Diagnose the O2 Sensor system and replace faulty components.
Source: OBD-II Manufacturer Extended Codes / SAE J2012 / OBD-Codes.com
Category: OBD-II