P1327
Knock Sensor 2 Bank 1 Low Input.
- BMW
- Powertrain
- Manufacturer code
- Medium severity
How this code is built
- P
- SystemPowertrain
- 1
- Defined byThe manufacturer
- 3
- AreaIgnition system or misfire
- 27
- FaultThe specific fault in that area
What it means
On BMW, P1327 means the engine control unit has seen a signal voltage that is too low from knock sensor 2 on bank 1. The control unit monitors the sensor's signal circuit, and a reading below the expected range suggests a short to ground, an open or high-resistance circuit, or a failed sensor. With no reliable knock signal, the control unit may pull ignition timing back to protect the engine.
Symptoms
- Engine warning light on
- Noticeable loss of power or flat acceleration
- Poorer fuel economy
- Rougher running or hesitation under load
- Possible pinking or knocking under load if the sensor is not reading correctly
Possible causes
- Damaged, chafed or oil-soaked wiring to knock sensor 2, causing a short to ground or high resistancelikely
- Faulty knock sensor 2 on bank 1likely
- Corroded, contaminated or loose connector at the sensor or control unitpossible
- Sensor loose or incorrectly torqued, or a poor mounting surfacepossible
- Coolant or oil leak dripping onto the sensor or connector and affecting the signalpossible
- Fault inside the engine control unit's knock sensing circuitrare
How to diagnose
- Read all stored and pending codes and the freeze frame data, noting engine load, speed and temperature when the fault set
- Check the location and routing of knock sensor 2 for your specific engine, as the position and harness path vary by model and engine
- Visually inspect the sensor wiring and connector for chafing, heat damage, oil or coolant contamination, bent pins and corrosion
- Check for oil or coolant leaks above or around the sensor and harness
- Check the sensor is fitted correctly and tightened to the manufacturer's torque
- Measure the sensor circuit for continuity, short to ground and resistance against the manufacturer's specification for your engine
- Check live data to see whether the sensor signal responds, comparing it with the other knock sensors
- Clear the code and road test to see whether it returns immediately, which points to a hard fault, or only later, which points to an intermittent fault
How to fix
- Repair or replace damaged wiring and fix the cause of any chafing
- Clean or replace a corroded or contaminated connector and terminals
- Replace knock sensor 2 with a correct part and tighten it to the specified torque
- Repair any leak that is contaminating the sensor or harness
- Replace the engine control unit only if the wiring and sensor test fine and the fault is confirmed in the unit
Can I keep driving?
The car can usually be driven for a short time, but power will be reduced while the control unit protects the engine. Avoid heavy loads and hard acceleration, and have it fixed soon, as running without proper knock detection risks engine damage.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.