Symptom
Engine pinking or knocking under load
A sharp metallic rattle when accelerating or climbing, caused by uncontrolled combustion. Damaging if sustained, and often relieved immediately by using the correct fuel grade.
Also described as: pinking, pinging, detonation, knocking under load, spark knock, pre-ignition, rattling under acceleration, knock threshold, صدای ضربه موتور زیر بار, موتور ناک میزند, صدای تقه در سربالایی, motor pica al acelerar, detonacion motor, cascabeleo bajo carga, motor cascabelea, خبط المحرك عند التحميل, صوت دقدقة عند الصعود, طرق في المكينة
What this usually means
A sharp metallic rattle when accelerating or climbing, caused by uncontrolled combustion — the mixture igniting ahead of, or against, the flame front rather than burning smoothly away from the spark. Damaging if sustained, because the pressure spike lands on the piston crown and the bearings at the worst possible moment.
Often relieved immediately by using the correct fuel grade, and that is the first thing to establish because it is free. An engine specified for higher-octane fuel run on lower will pink under load, and the management retards ignition to protect itself — so the symptom may be accompanied by a quiet loss of performance that nobody connects to the fuel.
Carbon deposits are the next population. Build-up in the combustion chamber raises the effective compression ratio and provides hot spots that ignite the mixture early — which is why the fault often appears gradually on a car used for short journeys.
Then the things that make combustion hotter or leaner. An exhaust gas recirculation valve stuck closed removes the inert gas that lowers peak temperature. A lean mixture from an air leak or a failing injector burns hotter. Overheating does it too, so a car that pinks and runs warm has one fault rather than two.
And the knock sensor itself. The management listens for this noise and retards ignition when it hears it — so a failed sensor removes the protection and lets an engine pink that would otherwise have quietly protected itself. That is worth checking because the symptom is the safety system being absent rather than a new cause appearing.
Do not drive hard while it pinks. Sustained detonation damages pistons and bearings quickly.
Working through it
| What you find | Likely cause | How to confirm it | What fixes it |
|---|---|---|---|
| Started after filling with a lower-grade fuel | Octane below what the engine needs — the cheapest cause and the quickest to test | Check the required grade on the filler flap and in the handbook, then run a tank of the correct fuel. | Use the specified grade. Performance often returns with it, since the management was retarding ignition. |
| Gradual onset on a car used for short journeys | Carbon deposits raising effective compression and creating hot spots | Borescope through the plug holes if available. The use pattern is itself supporting evidence. | Decarbonise by the manufacturer's approved method. Change the use pattern or it returns. |
| Pinking with the temperature gauge above normal | Overheating raising combustion temperature — one fault, two symptoms | Treat as an overheating complaint first. Pinking is a consequence here rather than a cause. | Repair the cooling fault. See the temperature-gauge entry in this vocabulary. |
| Pinking with lean fuel trims or an EGR fault stored | A lean mixture, or exhaust gas recirculation not lowering peak temperature | Read trims and command the EGR valve while watching its position feedback. | Repair the air leak or free the valve. Both raise combustion temperature directly. |
| Pinking with no other fault and correct fuel | The knock sensor — the protection that would normally retard ignition has stopped working | Read knock sensor codes and live ignition retard. An engine that pinks with no retard applied is not being protected. | Renew the sensor and check its torque, which affects its ability to hear the engine at all. |
| Heavy metallic knock that does not vary with throttle | Not pinking — mechanical knock from bearing wear | Pinking follows load and throttle; bearing knock follows engine speed and worsens with load but does not stop on lift. | Stop driving. See the unusual-engine-noise entry, which treats bottom-end noise as a stop-driving matter. |
-
Started after filling with a lower-grade fuel
- Likely cause
- Octane below what the engine needs — the cheapest cause and the quickest to test
- How to confirm it
- Check the required grade on the filler flap and in the handbook, then run a tank of the correct fuel.
- What fixes it
- Use the specified grade. Performance often returns with it, since the management was retarding ignition.
-
Gradual onset on a car used for short journeys
- Likely cause
- Carbon deposits raising effective compression and creating hot spots
- How to confirm it
- Borescope through the plug holes if available. The use pattern is itself supporting evidence.
- What fixes it
- Decarbonise by the manufacturer's approved method. Change the use pattern or it returns.
-
Pinking with the temperature gauge above normal
- Likely cause
- Overheating raising combustion temperature — one fault, two symptoms
- How to confirm it
- Treat as an overheating complaint first. Pinking is a consequence here rather than a cause.
- What fixes it
- Repair the cooling fault. See the temperature-gauge entry in this vocabulary.
-
Pinking with lean fuel trims or an EGR fault stored
- Likely cause
- A lean mixture, or exhaust gas recirculation not lowering peak temperature
- How to confirm it
- Read trims and command the EGR valve while watching its position feedback.
- What fixes it
- Repair the air leak or free the valve. Both raise combustion temperature directly.
-
Pinking with no other fault and correct fuel
- Likely cause
- The knock sensor — the protection that would normally retard ignition has stopped working
- How to confirm it
- Read knock sensor codes and live ignition retard. An engine that pinks with no retard applied is not being protected.
- What fixes it
- Renew the sensor and check its torque, which affects its ability to hear the engine at all.
-
Heavy metallic knock that does not vary with throttle
- Likely cause
- Not pinking — mechanical knock from bearing wear
- How to confirm it
- Pinking follows load and throttle; bearing knock follows engine speed and worsens with load but does not stop on lift.
- What fixes it
- Stop driving. See the unusual-engine-noise entry, which treats bottom-end noise as a stop-driving matter.
Codes that produce this symptom (39)
Listed with the codes that most typically present this way first — the likeliest place to start.
- P01CC Cylinder 1 Injection Timing Performance - Over Advanced Typical of this code Moderate
- P01CE Cylinder 2 Injection Timing Performance - Over Advanced Typical of this code Moderate
- P01D0 Cylinder 3 Injection Timing Performance - Over Advanced Typical of this code Moderate
- P01D2 Cylinder 4 Injection Timing Performance - Over Advanced Typical of this code Moderate
- P01D4 Cylinder 5 Injection Timing Performance - Over Advanced Typical of this code Moderate
- P01D6 Cylinder 6 Injection Timing Performance - Over Advanced Typical of this code Moderate
- P2191 System Too Lean at Higher Load Bank 1 Typical of this code Moderate
- P2336 Cylinder 1 Above Knock/Combustion Vibration Sensor Threshold Typical of this code High
- P2337 Cylinder 2 Above Knock/Combustion Vibration Sensor Threshold Typical of this code High
- P2338 Cylinder 3 Above Knock/Combustion Vibration Sensor Threshold Typical of this code High
- P2339 Cylinder 4 Above Knock/Combustion Vibration Sensor Threshold Typical of this code High
- P2340 Cylinder 5 Above Knock/Combustion Vibration Sensor Threshold Typical of this code High
- P2341 Cylinder 6 Above Knock/Combustion Vibration Sensor Threshold Typical of this code High
- P2342 Cylinder 7 Above Knock/Combustion Vibration Sensor Threshold Typical of this code High
- P2343 Cylinder 8 Above Knock/Combustion Vibration Sensor Threshold Typical of this code High
- P2344 Cylinder 9 Above Knock/Combustion Vibration Sensor Threshold Typical of this code High
- P2345 Cylinder 10 Above Knock/Combustion Vibration Sensor Threshold Typical of this code High
- P2346 Cylinder 11 Above Knock/Combustion Vibration Sensor Threshold Typical of this code High
- P2347 Cylinder 12 Above Knock/Combustion Vibration Sensor Threshold Typical of this code High
- P020A Cylinder 1 Injection Timing Moderate
- P026B Injection Timing Performance Moderate
- P0324 Knock/Combustion Vibration Control System Error High
- P0326 Knock/Combustion Vibration Sensor A Circuit Range/Performance Moderate
- P032A Knock/Combustion Vibration Sensor C Circuit Moderate
- P032D Knock/Combustion Vibration Sensor C Circuit High Moderate
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
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