P0389moderate severityPowertrain
Auxiliary/Secondary Knock Sensor 2 Circuit Intermittent
on 2007 Mercedes-Benz S65 AMG 6.0L V12 BiTurbo M275 · RWD
What this code means
The PCM sees an intermittent or erratic signal from the second knock sensor circuit. The problem may come and go with vibration or temperature changes.
Symptoms
- Intermittent check engine light
- Occasional power loss
- Random engine pinging
Common causes
- Loose or corroded connector
- Chafed sensor wiring
- Faulty knock sensor 2
- Loose sensor mounting
Diagnostic steps
- Retrieve stored and pending codes
- Wiggle-test sensor wiring while monitoring
- Inspect sensor torque and mounting surface
- Repair harness or replace sensor as needed
🔌 Don't have a code reader?
Any of these will read and clear this code — pick by how deep you want to go.
Budget handheld~$40
ANCEL AD410 →
No-phone-needed handheld — reads, clears, live data, freeze frame.
✓ ANCEL official store
Serious DIY~$100
BlueDriver Pro →
Enhanced codes (ABS, airbag, TPMS) plus repair reports.
SHOP FAVORITEShop-grade tablet~$300
Autel MaxiCOM MK808S →
Bidirectional tests, service resets, all systems.
✓ Autel official store
Pro diagnostics$1,500+
Autel MaxiSys MS906 Pro →
Full-system pro platform — topology mapping, ECU coding, the works.
✓ Autel official store
As an Amazon Associate and Autel/ANCEL partner, OLP earns from qualifying purchases — how we link. This never changes the specs we publish.
Other Powertrain codes on this vehicle
P0001
Fuel Volume Regulator Control Circuit/Open
P0002
Fuel Volume Regulator Control Circuit Range/Performance
P0003
Fuel Volume Regulator Control Circuit Low
P0004
Fuel Volume Regulator Control Circuit High
P0005
Fuel Shutoff Valve A Control Circuit/Open
P0006
Fuel Shutoff Valve A Control Circuit Low
P0007
Fuel Shutoff Valve A Control Circuit High
P0008
Engine Position System Performance - Bank 1
P0009
Engine Position System Performance - Bank 2
P0010
Intake Camshaft Position Actuator Circuit/Open Bank 1