01 P0075, P0076, and P0077: Intake valve control solenoid circ… • 02 All-New Lexus GX Overtrail (2024) - The Rugged Luxury SUV • 03 P0013 B Camshaft Position - Actuator Circuit (Bank 1) • 04 These Simple Car Maintenance Hacks Have Never Been This Easy • 05 A Comprehensive Guide to Different Types of Automotive Bulbs • 06 U0009 High Speed CAN Communication Bus (-) shorted to Bus (… • 07 P0016 - Crankshaft Position Camshaft Position Correlation B… • 08 U0021, U0022, U0023, U0024, U0025 and U0026: Low Speed CAN … • 09 Can a Hybrid Car Run on EV Mode All the Time? • 10 Drivers Are Left Stunned After Discovering The Real Purpose… •

DTC codes / Volkswagen codes / P1198

P1198 · VolkswagenOxygen Sensor Heater Circuit Bank 1 Sensor 2 Electrical Malfunction

P1198 on Volkswagen vehicles indicates that the engine control module has detected an electrical fault in the heater circuit of the downstream oxygen sensor on bank 1, which is the sensor after the catalytic converter. The computer monitors the heater element's current draw and expects a specific resistance range when the heater is commanded on, and this code sets when the circuit is open, shorted to ground, or shorted to power.

SystemPowertrain
Code typeVolkswagen specific
SeverityLow
Fix difficultyIntermediate
AreaFuel and air metering

Symptoms you may notice

  • Illumination of the check engine light, often with no other noticeable symptoms
  • Slightly higher fuel consumption because the sensor takes longer to reach operating temperature
  • A pending or stored code that returns quickly after clearing if the fault is permanent
  • In rare cases, a rough idle or hesitation during cold starts if the sensor heater also affects the sensor signal
  • No driveability complaints at all when the fault is limited to the heater element

Common causes, most likely first

  1. Failed oxygen sensor heater element inside the downstream sensor
  2. Corroded, loose, or damaged electrical connector at the sensor
  3. Broken or chafed wiring between the sensor and the engine control module
  4. Blown fuse that supplies power to the oxygen sensor heater circuit
  5. Faulty engine control module driver for the heater circuit, though this is less common
  6. Water intrusion into the connector or wiring harness causing corrosion

How to diagnose and fix it

  1. Check the fuse that feeds the oxygen sensor heater circuit and replace it if blown
  2. Inspect the sensor connector and wiring for corrosion, damage, or loose pins, and repair as needed
  3. Measure the resistance of the heater element at the sensor connector and compare to the manufacturer's specification
  4. Check for power and ground at the heater circuit with the key on and the engine running
  5. If the circuit checks out, replace the downstream oxygen sensor with a quality part
  6. Clear the code and verify the repair by running the oxygen sensor heater monitor to completion
  7. If the code persists after sensor replacement, trace the wiring back to the engine control module and check for continuity and shorts

Don't overlook the heater fuse and wiring

  • A blown fuse for the oxygen sensor heater circuit is a common cause that many people miss because they replace the sensor first without checking the fuse.
  • The downstream sensor heater can fail while the sensor still produces a plausible signal, so the engine may run fine and the only clue is the stored code.
  • Corrosion inside the connector is a frequent culprit on Volkswagens, especially in regions where road salt is used, and it can mimic a failed sensor.
  • This code does not always mean the sensor itself is bad; a shorted or open wire between the sensor and the engine control module will set the same code.
  • After replacing the sensor, the heater monitor must run before the code will clear from the system, so a short drive cycle may be needed to confirm the repair.

Can I keep driving with P1198?

You can usually continue driving with this code because the downstream oxygen sensor heater only affects emissions and cold-start sensor readiness, but avoid long periods of idling or cold-weather driving until repaired. Have the fault diagnosed soon to prevent unnecessary emissions and to ensure the sensor provides accurate feedback for fuel control.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for Volkswagen vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

Running on fumes Free guides aren't free to make. Top up the tank. Any amount, one time. Fuel the Garage