Will Rod Knock Cause Check Engine Light?

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Will Rod Knock Cause Check Engine Light

Rod knock is a common type of engine concern that can happen in both old and new cars, sound similar to a knocking noise. While it is a serious issue that can cause severe damage to the engine if left unresolved, the question remains, is rod knock something that can trigger the check engine light? In this blog post, we will investigate whether rod knock can cause a check engine light to illuminate.

what rod knock is and how it occurs?

rod knock

Rod knock happens when the rod bearings and connecting rods suffer excessive wear or become loose due to lack of lubrication or bad oil pressure, causing the rod to knock against the engine block, creating a distinctive knocking noise. The knocking noise is a severe indication of engine damage, and if left unaddressed, it can result in engine failure.

Does rod knock trigger a check engine light?

Now we come to the question of whether rod knock triggers a check engine light. The answer is no. The check engine light is controlled by the car’s computer systems and is primarily designed to diagnose emissions systems, including the oxygen sensor, catalytic converter, and EVAP system. Rod knock does not have a direct connection to any of these systems, so the ECM cannot directly detect it and send the signal to the light.

However, it is essential to note that if the rod knock worsens, it can lead to other issues that cause the check engine light to illuminate. For instance, if the knocking causes misfires, it can trigger the oxygen sensor, which in turn causes the check engine light to come on. Similarly, if the knocking damages the catalytic converter, it can trigger the light to come on. Therefore, while the rod knock itself cannot trigger the check engine light, it could indirectly cause it.

It is vital to take any knocking or unusual noise coming from your car’s engine seriously. If your car starts producing a loud knocking noise, it is crucial to address it immediately. Delaying the repair can lead to severe engine damage and costly repairs that could have been avoided. Moreover, you could risk violating your warranty terms if you continue driving the car with a knocking engine, causing you to pay out of your pocket for repairs.


Rod knock is a severe engine problem that can cause loud knocking noises and even lead to engine damage and failure if left unrepaired. However, it cannot directly trigger the check engine light. It is essential to have any unusual noises or knocking sounds inspected by a mechanic immediately. Although rod knock does not cause the check engine light to come on, repairs are necessary if you want to prolong the life of your vehicle and save money in the long run.

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