Code
P1012
DACIA
P — Powertrain
Knock sensor (KS), bank 1 - circuit malfunction
AI status
Completed
Completed
100%
Causes
- Open, shorted or damaged wiring between KS (bank 1) and the ECU
- Corroded, loose or contaminated sensor connector
- Failed knock sensor (open, shorted or no output)
- Poor sensor grounding or ECU connector fault
- Sensor mounting loose or missing torque/isolator
- Intermittent connection due to heat, vibration or rodent damage
Symptoms
- Malfunction Indicator Lamp (MIL/Check Engine) illuminated
- Reduced ignition timing advance under load or richer fueling
- Possible loss of performance, hesitation or pinging under load
- Lower fuel economy
- No knock diagnostics available (engine may run more conservatively)
- DTC may be intermittent if wiring is intermittent
What to check
- Read freeze frame and all stored codes; note conditions when code set (load, RPM, temperature)
- Check for related codes (crank/cam sensors, other KS codes) and history
- Perform a visual inspection of the knock sensor, connector, and wiring harness for damage, corrosion, or heat chafing
- Backprobe the sensor connector and monitor signal with scan tool / oscilloscope while cranking and under load
- Check continuity between KS connector and ECU pin(s); check for short to ground or battery
- Wiggle harness and connector while monitoring live data to check for intermittent faults
Signal parameters
- Knock sensor is a piezoelectric sensor that produces AC voltage pulses when engine knock occurs; the ECU looks for pulse patterns rather than a steady DC voltage
- Expected behavior: near-zero steady signal at idle with transient pulses under load/knock; amplitude increases with knock intensity
- Fault indicators: open circuit (infinite resistance/no voltage), constant 0 V, constant short to battery/ground or no pulse activity under load
- Best measurement tool: oscilloscope; scan tool may show 'knock' counts or a live parameter for sensor activity
- Resistance checks can indicate open/short but some KS types show very high impedance—refer to specific service manual values before relying on ohms measurement
Diagnostic algorithm
- Retrieve all codes and freeze-frame data. Note engine temperature, RPM, and load when P1012 set.
- Clear codes and attempt to reproduce. If code returns, proceed with diagnosis.
- Visually inspect knock sensor, wiring and connector for damage, corrosion, heat damage or loose mounting.
- Backprobe the sensor connector. With the engine off, check for continuity between sensor signal pin and ECU input pin; check for short to ground or to battery.
- Start engine and monitor live data/knock counts. Use an oscilloscope on the signal wire and observe waveform while revving and under load. Look for pulses that vary with RPM/load.
- Wiggle test the harness and connector while monitoring signal to detect intermittent wiring faults.
- Verify sensor mounting: remove and inspect mounting hole and bolt, ensure proper torque and that the sensor sits flat on the block/exhaust face as specified by manufacturer.
- If wiring and mounting are good but no valid signal, replace the knock sensor with a correct OEM or specified part and retest.
- If replacement does not resolve the issue, check ECU connector and grounds; if wiring and ECU pins pass checks consider ECU fault or require specialist diagnostic equipment/ dealer support.
- After repair, clear codes and perform road test under the same conditions to confirm fault does not return.
Likely causes
- Damaged wiring or connector at the sensor (most common)
- Corroded/loose sensor connector
- Failed knock sensor (piezo element degraded or open)
- Sensor improperly mounted or missing spacer/isolator
- Intermittent harness fault near exhaust or engine mount areas
Fault status
Status
Knock sensor (KS), Bank 1 - circuit malfunction
Repair difficulty: Medium
Diagnostic time: 0.8-2.0 hours
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