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DTC codes / Volkswagen codes / P1115

P1115 · VolkswagenOxygen Sensor Heater Circuit Short To Ground Bank 1 Sensor 1

This code means the engine control module (ECM) has detected an abnormally low voltage on the heater circuit for the pre-catalytic oxygen sensor on bank 1, indicating a short to ground. The ECM expects to see battery voltage on the heater control circuit when the heater is commanded on, and a short to ground pulls that voltage down, setting the fault.

SystemPowertrain
Code typeVolkswagen specific
SeverityMedium
Fix difficultyIntermediate
AreaFuel and air metering

Symptoms you may notice

  • Illuminated check engine light, often with no other noticeable symptoms
  • Slightly rough idle or hesitation when the engine is cold, because the oxygen sensor takes longer to reach operating temperature
  • Increased fuel consumption as the ECM may run a richer mixture while the sensor is not ready
  • Failed emissions test due to the oxygen sensor heater not functioning
  • In some cases, a stored pending code or freeze-frame data showing low heater circuit voltage

Common causes, most likely first

  1. Oxygen sensor heater element internally shorted to ground
  2. Chafed or damaged heater circuit wiring shorting to ground on the engine block or chassis
  3. Corroded or water-intruded connector at the oxygen sensor or ECM
  4. Faulty ECM driver for the oxygen sensor heater circuit (less common)
  5. Aftermarket or incorrect oxygen sensor with a heater resistance that does not match the ECM's expectations

How to diagnose and fix it

  1. Scan all modules and record freeze-frame data to confirm the code is active and not a historical glitch
  2. Visually inspect the oxygen sensor harness and connector for chafing, corrosion, or moisture intrusion
  3. Measure the resistance of the oxygen sensor heater element with a multimeter and compare to the manufacturer's specification
  4. Disconnect the sensor and check for continuity to ground on the heater control wire; repair any short to ground
  5. Check the heater circuit for proper voltage supply and ground integrity at the sensor connector with the key on
  6. If wiring and supply are good, replace the oxygen sensor with an OEM-quality part
  7. Clear the code and perform a road test to verify the heater circuit operates correctly and the code does not return

What a shorted heater circuit really means

  • A short to ground in the heater circuit often does not disable the oxygen sensor signal entirely, so the engine may run almost normally and the only clue is the stored code.
  • The heater element can short internally only when hot, so a cold resistance check may pass; a wiggle test or a heat gun on the sensor can reveal an intermittent short.
  • Water intrusion into the sensor connector is a common Volkswagen-specific cause, especially after steam cleaning or driving through deep puddles, and it can mimic a failed sensor.
  • Replacing the oxygen sensor without checking the heater control wire for a rub-through against the heat shield or block frequently leads to a repeat failure.
  • A shorted heater can draw excessive current and damage the ECM driver, so ignoring the code may turn a cheap sensor repair into an expensive module replacement.

Can I keep driving with P1115?

You can usually drive the vehicle short distances to a repair shop, but avoid heavy load or long trips because the oxygen sensor heater will not function and the engine may run richer than normal. Have the fault diagnosed promptly to prevent potential ECM damage.

Tools that help

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

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