Code
P1330
PEUGEOT
P — Powertrain
Cylinder 2 knock adjust limiter malfunction
Views:
UK: 0
EN: 3
RU: 2
AI status
Completed
Completed
100%
Causes
- Faulty knock sensor on cylinder 2
- Open, short or intermittent wiring/connector between knock sensor and engine control module (ECM)
- Poor sensor mounting (loose, broken stud or damaged boss) or oil/contaminant on sensor
- Internal ECM/knock control circuit fault or software/adaptation error
- Excessive engine detonation/knock causing the limiter to engage
- Related timing, fueling or ignition issues producing abnormal knock signatures
Symptoms
- Malfunction Indicator Lamp (MIL) / check engine light illuminated
- Knock control adaptation limited or disabled for cylinder 2 — possible reduced performance or drivability
- Intermittent or persistent engine knock audible under load
- Poor idle, hesitations or reduced power when knock control is limited
- Possible increase in fuel consumption or emissions
What to check
- Read stored DTCs and freeze-frame data with a capable scan tool
- Check live data: knock sensor signal for cylinder 2 and compare to other cylinder(s) during cranking and under load
- Visual inspection of knock sensor, mounting stud, and surrounding area for oil, carbon, damage or loose fasteners
- Inspect wiring harness and connector for corrosion, bent terminals, damaged insulation or poor pins
- Check for related DTCs (ignition, fueling, timing, other knock sensor codes)
- Clear code and perform a road test/loaded acceleration to see if code returns
Signal parameters
- Sensor type: piezoelectric vibration sensor mounted to engine block/near cylinder head
- Typical output: AC transient pulses (low voltage) corresponding to knock events; healthy pulses are short, spike-like and occur in the kHz range
- Expected waveform: brief high-frequency spikes during knock; amplitude varies with severity (often fractions to a few volts depending on conditioning circuitry)
- ECM compares amplitude and frequency content between cylinders and uses adaptive trimming — P1330 means the limiter/adjust function for cylinder 2 is not working within expected parameters
Diagnostic algorithm
- Read all codes and freeze-frame data; note conditions when P1330 set (load, RPM, engine temp).
- Attempt to reproduce: clear code, monitor knock sensor signals for cylinder 2 while performing controlled loaded acceleration and deceleration tests. Compare with other cylinder knock sensors if available.
- Perform visual inspection of sensor and mounting area. Check sensor tightness and for oil/fouling. Re-torque sensor to manufacturer spec if loose.
- Inspect connector and wiring: unplug and inspect pins for corrosion/contamination or damage. Wiggle harness while monitoring live signal to look for intermittent behavior.
- Measure sensor resistance (if specified by manufacturer) and continuity between sensor and ECM connector; check for short to ground or battery. Replace sensor if out of spec.
- Back-probe the sensor signal with an oscilloscope or a graphing scan tool while cranking/under load to confirm presence/quality of knock pulses. Compare waveform to a known-good sensor or cylinder.
- If possible, swap the suspect sensor with a known-good sensor from another cylinder (if identical) and re-scan: if code follows sensor, replace sensor; if it remains on cylinder 2, suspect wiring/ECM.
- Check for mechanical causes of knock (incorrect ignition timing, low octane fuel, carbon build-up, pre-ignition); correct any findings and retest.
- If wiring and sensor check good, consider ECM fault or internal knock circuit failure — consult manufacturer service info for ECM testing or reflash/ECM replacement.
- After repairs, clear codes and perform a full verification road test and re-check adaptation values; ensure code does not return.
Likely causes
- Faulty or degraded knock sensor at cylinder 2
- Damaged/loose connector or wiring harness (open, short to ground, short to battery) to the sensor
- Sensor mounting loose or contaminated (oil, carbon) preventing correct vibration pickup
- ECM knock circuit fault or corrupted adaptation values
Fault status
Status
Cylinder 2 knock-adjust limiter malfunction — knock control for cylinder 2 has been limited or disabled due to a sensor/circuit fault.
Repair difficulty: Medium
Diagnostic time: 1.0 - 2.5 hours
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