Knock Sensor 4 Circuit Low (Bank 2)
This code means the PCM/ECM has detected a low-voltage circuit condition affecting knock sensor 4. Because combustion on the affected cylinder or circuit is disrupted, drivers may notice rough running, misfires, hard starts, or reduced power.
What You Might Notice
- Check Engine Light illuminated
- Rough idle or misfire
- Hard starting
- Reduced power
- Poor fuel economy
Most Common Causes
- 1
Short to ground or excessive resistance in the circuit
- 2
Damaged wiring or poor connector contact
- 3
Worn spark plug or combustion problem
- 4
Low system voltage or ground issue
- 5
PCM/ECM driver fault
How to Diagnose It
- 1
Check Short to ground or excessive resistance in the circuit — Inspect for signs of failure and test before replacing.
- 2
Check Damaged wiring or poor connector contact — Inspect for signs of failure and test before replacing.
- 3
Check Worn spark plug or combustion problem — Inspect for signs of failure and test before replacing.
- 4
Check Low system voltage or ground issue — Inspect for signs of failure and test before replacing.
- 5
Check PCM/ECM driver fault — Inspect for signs of failure and test before replacing.
How to Fix It
- 1
Test the affected coil, glow plug, or ignition-related component
- 2
Inspect spark plugs and basic engine condition
- 3
Repair damaged wiring, grounds, or connector pins
- 4
Replace the failed ignition-related part
- 5
Clear the code and confirm the symptom is gone
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