Internal short in the Bank 1 Sensor 1 oxygen sensor heater element; Chafed or damaged sensor wiring shorting to ground, often near the exhaust, engine or bracket; Corroded, damaged or wet connector at the sensor or in-line plug; Heater control wire shorted to ground elsewhere in the harness; Fault in the engine control unit heater driver output; Heat damage to the sensor lead from contact with the exhaust manifold or downpipe.

P1115

Oxygen Sensor Heater Circuit Short To Ground Bank 1 Sensor 1.

Volkswagen
Powertrain
Manufacturer code
Low severity

How this code is built

P: SystemPowertrain
1: Defined byThe manufacturer
1: AreaFuel and air metering
15: FaultThe specific fault in that area

What it means

On a Volkswagen, P1115 means the engine control unit has detected a short to ground in the heater circuit of the upstream oxygen sensor (Bank 1 Sensor 1, the sensor ahead of the catalytic converter). The control unit drives the heater to bring the sensor up to working temperature quickly, and it saw the heater control line pulled to ground or an abnormally low voltage where it expected normal switching.

Symptoms

Engine management warning light on
Engine may run in open-loop, giving slightly poor fuel economy
Rough idle or hesitation, particularly on a cold start
Slightly higher exhaust emissions or a failed emissions test
Possible slow or erratic fuel trim behaviour until the sensor warms up

Possible causes

Internal short in the Bank 1 Sensor 1 oxygen sensor heater elementlikely
Chafed or damaged sensor wiring shorting to ground, often near the exhaust, engine or bracketlikely
Corroded, damaged or wet connector at the sensor or in-line plugpossible
Heater control wire shorted to ground elsewhere in the harnesspossible
Fault in the engine control unit heater driver outputrare
Heat damage to the sensor lead from contact with the exhaust manifold or downpipepossible

How to diagnose

Read the stored fault codes and freeze frame data, note whether the fault is current or intermittent, and check for other oxygen sensor or fuel trim codes.
Visually inspect the Bank 1 Sensor 1 wiring and connector for chafing, melting, corrosion, water ingress or contact with hot exhaust parts.
Check the live data for the sensor heater status or heater duty, if available, and see whether the control unit is commanding the heater.
With the ignition off and the connector unplugged, measure the heater element resistance across its heater terminals and compare it with the specification for your engine and sensor type.
Check the heater control and supply wires for a short to ground, and the sensor body for continuity to earth, using the wiring diagram for your model.
Check the heater supply voltage and fuse or relay feed to the sensor, as the layout varies by model and engine.
If the sensor and wiring are sound, check the control unit output and connector pins, and look for any applicable software updates for your model.

How to fix

Replace the Bank 1 Sensor 1 oxygen sensor if the heater element is shorted or out of specification.
Repair or replace damaged wiring, and secure it clear of hot or moving parts.
Clean, dry and repair the connector, or replace the terminals or plug if corroded or damaged.
Repair the harness short to ground found between the sensor and the control unit.
Repair or replace the engine control unit only after all wiring and sensor faults are ruled out, and only if the output is confirmed faulty.

Can I keep driving?

Low severity

The car can usually be driven short term, as the fault mainly affects sensor warm-up and mixture control. Book it in soon, as a prolonged fault can worsen economy and emissions and may strain the catalytic converter.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.