Lambda with api gateway lambda_proxy integration error response

Hi!. I succesfully achieve to make lambda returning status code 400 and a message to the client. But in cloudwatch logs that execution even if i return status code 400 its returned like a success execution. I want to be able to "mark" that execution as an error and return the client a corresponding message with status code 400.
This is how i am returning the error

console.error(err);
response = {
'statusCode': 400,
headers: {

            "Access-Control-Allow-Origin": "*",  
        },  
        'body': 'Error al obtener productos'  
    }  

return response;  

Thanks in advance.
Pamela