What Does P1198 Mean?
The heater circuit for the downstream oxygen sensor on Bank 1 (side with cylinder #1) has an electrical fault. The heater helps the O2 sensor reach operating temperature quickly for accurate readings.
Common Causes
35%
Faulty oxygen sensor heater element
30%
Damaged or corroded wiring/connectors to O2 sensor heater
20%
Blown fuse or bad relay for O2 heater circuit
15%
ECM internal driver circuit failure
Diagnostic Steps
1
Step 1: Inspect O2 sensor connector for corrosion, damage, or loose connection
2
Step 2: Check fuse and relay for O2 heater circuit
3
Step 3: Measure resistance of O2 sensor heater element (typically 4-8 ohms when cold)
4
Step 4: Check voltage supply to O2 sensor heater circuit (should have battery voltage)
5
Step 5: Test continuity and resistance of wiring harness between ECM and O2 sensor
Estimated Repair Cost
$150 - $400
Parts + labor, varies by vehicle and location
The heater circuit for the downstream oxygen sensor on Bank 1 (side with cylinder #1) has an electrical fault. The heater helps the O2 sensor reach operating temperature quickly for accurate readings.
The most common cause of P1198 (O2 Sensor Heater Circ.,Bank1-Sensor2 Electrical Malfunction) is: Faulty oxygen sensor heater element
Typical repair costs for P1198 range from $150 to $400, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to drive short distances. May cause increased emissions and reduced fuel economy.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1198 to identify the root cause.
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Quick Info
Category
Powertrain
System
Emissions System
Difficulty
Type
Manufacturer
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